Remove publish sources (#6427)

Per [b/377292172](https://b.corp.google.com/issues/377292172),

This fixes the issue with source jars not being published. Android
variants are configured at configuration time, but `withSourcesJar` is
only a function. There's no way to provide a `Provider` to defer setting
it. Attempting to instead call it after evaluation will result in it not
actually being set.

Previously, we published sources jars regardless if `publishSources` was
set to false. Furthermore, no SDK actually had it set to false anyhow.

So moving forward, I've just removed the setting entirely- as it wasn't
really being used, it fixes our issue, and reduces maintenance costs.

NO_RELEASE_CHANGE

Author: daymxn

appcheck/firebase-appcheck-debug-testing/firebase-appcheck-debug-testing.gradle

@@ -20,7 +20,6 @@ plugins {
 firebaseLibrary {
     libraryGroup = "appcheck"
     testLab.enabled = true
-    publishSources = true
     releaseNotes {
         name.set("{{app_check}} Debug Testing")
         versionName.set("appcheck-debug-testing")

appcheck/firebase-appcheck-debug/firebase-appcheck-debug.gradle

@@ -18,7 +18,6 @@ plugins {
 
 firebaseLibrary {
     libraryGroup = "appcheck"
-    publishSources = true
     releaseNotes {
         name.set("{{app_check}} Debug")
         versionName.set("appcheck-debug")

appcheck/firebase-appcheck-interop/firebase-appcheck-interop.gradle

@@ -17,7 +17,6 @@ plugins {
 }
 
 firebaseLibrary {
-    publishSources = true
     publishJavadoc = false
     releaseNotes { 
         enabled.set(false)

appcheck/firebase-appcheck-playintegrity/firebase-appcheck-playintegrity.gradle

@@ -18,7 +18,6 @@ plugins {
 
 firebaseLibrary {
     libraryGroup = "appcheck"
-    publishSources = true
     releaseNotes {
         name.set("{{app_check}} Play integrity")
         versionName.set("appcheck-playintegrity")

appcheck/firebase-appcheck/firebase-appcheck.gradle

@@ -19,7 +19,6 @@ plugins {
 
 firebaseLibrary {
     libraryGroup = "appcheck"
-    publishSources = true
     releaseNotes {
         name.set("{{app_check}}")
         versionName.set("appcheck")

appcheck/firebase-appcheck/ktx/ktx.gradle

@@ -24,7 +24,6 @@ firebaseLibrary {
     releaseNotes { 
         enabled.set(false)
     }
-    publishSources = true
 }
 
 android {

buildSrc/src/main/java/com/google/firebase/gradle/plugins/BaseFirebaseLibraryPlugin.kt

@@ -53,7 +53,6 @@ abstract class BaseFirebaseLibraryPlugin : Plugin<Project> {
     with(library) {
       previewMode.convention("")
       publishJavadoc.convention(true)
-      publishSources.convention(true)
       artifactId.convention(project.name)
       groupId.convention(project.provider { project.group.toString() })
       libraryGroup.convention(artifactId)

buildSrc/src/main/java/com/google/firebase/gradle/plugins/FirebaseAndroidLibraryPlugin.kt

@@ -18,7 +18,6 @@ package com.google.firebase.gradle.plugins
 
 import com.android.build.gradle.LibraryExtension
 import com.android.build.gradle.LibraryPlugin
-import com.android.build.gradle.internal.crash.afterEvaluate
 import com.google.firebase.gradle.plugins.LibraryType.ANDROID
 import com.google.firebase.gradle.plugins.ci.device.FirebaseTestServer
 import com.google.firebase.gradle.plugins.license.LicenseResolverPlugin
@@ -199,13 +198,8 @@ class FirebaseAndroidLibraryPlugin : BaseFirebaseLibraryPlugin() {
     firebaseLibrary: FirebaseLibraryExtension,
     android: LibraryExtension,
   ) {
-    android.publishing.singleVariant("release") {
-      project.afterEvaluate {
-        if (firebaseLibrary.publishSources.get()) {
-          withSourcesJar()
-        }
-      }
-    }
+    android.publishing.singleVariant("release") { withSourcesJar() }
+
     project.tasks.withType<GenerateModuleMetadata> { isEnabled = false }
 
     configurePublishing(project, firebaseLibrary)

buildSrc/src/main/java/com/google/firebase/gradle/plugins/FirebaseLibraryExtension.kt

@@ -69,20 +69,6 @@ constructor(val project: Project, val type: LibraryType) {
    */
   abstract val publishJavadoc: Property<Boolean>
 
-  /**
-   * Publish source files for this library.
-   *
-   * Publishing sources alongside your standard `jar` or `aar` allows the IDE to offer better
-   * auto-complete and inline linkage.
-   *
-   * If your SDK lives in the public repo, there's no real reason for you to have this disabled.
-   *
-   * Defaults to `true`.
-   *
-   * @see [FirebaseLibraryExtension]
-   */
-  abstract val publishSources: Property<Boolean>
-
   /**
    * Indicates the library is in a preview mode (such as `alpha` or `beta`).
    *