Fix 'duplicate class' error caused by incomplete kt stdlib metadata

When testing locally it seemed that upgrading KGP to `1.9.20` resolved
this, but testing again confirms this was incorrect, so the problem
was reintroduced in 00d1e70a34.

This change reverts back to KGP `1.9.0` (since upgrading didn't help)
and instead implements the workaround suggested in
https://issuetracker.google.com/278545487. The workaround is now in
the `lib-common` `build.gradle` file, which is transitively depended
on by all modules (and therefore all apps that use this library), so
there's no need for any developer action, and so the release note is
removed.

Issue: androidx/media#1262
PiperOrigin-RevId: 651066418

RELEASENOTES.md

@@ -11,15 +11,6 @@
     *   Add override for `SimpleBasePlayer.State.Builder.setPlaylist()` to
         directly specify a `Timeline` and current `Tracks` and `Metadata`
         instead of building a playlist structure.
-    *   Upgrade `androidx.annotation:annotation` dependency to `1.6.0`. This may
-        cause `duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations`
-        and similar errors for non-Kotlin apps that also depend on other libs
-        like `androidx.appcompat:appcompat`. This is due to
-        [incomplete version constraints in the Kotlin standard library](https://youtrack.jetbrains.com/issue/KT-55297).
-        Apps can resolve this by upgrading their
-        [Kotlin Gradle Plugin](https://kotlinlang.org/docs/gradle-configure-project.html#apply-the-plugin)
-        to at least version `1.9.20` or using the workaround described in
-        https://issuetracker.google.com/278545487.
 *   ExoPlayer:
     *   `MediaCodecRenderer.onProcessedStreamChange()` can now be called for
         every media item. Previously it was not called for the first one. Use

build.gradle

@@ -19,7 +19,7 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:8.3.2'
         classpath 'com.google.android.gms:strict-version-matcher-plugin:1.2.4'
-        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.20'
+        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.9.0'
     }
 }
 allprojects {

libraries/common/build.gradle

@@ -65,6 +65,11 @@ dependencies {
     }
     api 'androidx.annotation:annotation-experimental:' + androidxAnnotationExperimentalVersion
     implementation 'androidx.annotation:annotation:' + androidxAnnotationVersion
+    // Workaround for 'duplicate class' error caused by incomplete version
+    // metadata in Kotlin std lib (https://issuetracker.google.com/278545487).
+    // This can be removed when one of the other deps here (probably
+    // androidx.annotation) depends on kotlin-stdlib:1.9.20.
+    implementation platform('org.jetbrains.kotlin:kotlin-bom:1.8.0')
     compileOnly 'com.google.code.findbugs:jsr305:' + jsr305Version
     compileOnly 'com.google.errorprone:error_prone_annotations:' + errorProneVersion
     compileOnly 'org.checkerframework:checker-qual:' + checkerframeworkVersion