Remove unused Gradle dependencies

Remove dependencies flagged as unused by the Dependency Analysis Gradle Plugin
(`./gradlew buildHealth`) and explicitly declared in module build files.

Removals were skipped when the dependency provides transitively something the
module (or a consumer of an `api` dependency) uses directly, as well as for
runtime-only dependencies (element-call-embedded, sentry-android,
rustls-platform-verifier). Dependencies added by the convention plugin helpers
(composeDependencies, testCommonDependencies) are left untouched.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

libraries/mediaviewer/impl/build.gradle.kts

@@ -34,7 +34,6 @@ dependencies {
     implementation(libs.androidx.media3.exoplayer.midi)
     implementation(libs.androidx.media3.ui)
     implementation(libs.telephoto.zoomableimage)
-    implementation(libs.vanniktech.blurhash)
     implementation(libs.telephoto.flick)
 
     implementation(projects.features.enterprise.api)
@@ -47,7 +46,6 @@ dependencies {
     implementation(projects.libraries.dateformatter.api)
     implementation(projects.libraries.di)
     implementation(projects.libraries.designsystem)
-    implementation(projects.libraries.featureflag.api)
     implementation(projects.libraries.matrix.api)
     implementation(projects.libraries.matrixui)
     implementation(projects.libraries.matrixmedia.api)
@@ -66,9 +64,7 @@ dependencies {
     testImplementation(projects.features.enterprise.test)
     testImplementation(projects.libraries.audio.test)
     testImplementation(projects.libraries.dateformatter.test)
-    testImplementation(projects.libraries.featureflag.test)
     testImplementation(projects.libraries.matrix.test)
-    testImplementation(projects.libraries.matrixui)
     testImplementation(projects.libraries.mediaviewer.test)
     testImplementation(projects.services.toolbox.test)
     testImplementation(libs.coroutines.core)