Deps: Add transitive androidx compose ui unit dep to media ph

Although removing the 'androidx.compose.ui:ui' is enough by itself and
the build is okay, it is better to add 'androidx.compose.ui:ui-unit'
for transitive dependency related purposes.

FYI: It got introduced as part of this
(7d8d37c) commit, a part of
implementing placeholders in compose.

------------------------------------------------------------------------

This addition was suggested by the dependency analysis report, see
below:

These transitive dependencies should be declared directly:
  ...
  implementation 'androidx.compose.ui:ui-unit:1.7.5'
  ...

Author: ParaskP7

media-placeholders/build.gradle

@@ -49,6 +49,7 @@ dependencies {
     testImplementation "org.robolectric:robolectric:$robolectricVersion"
     implementation "androidx.compose.foundation:foundation:$androidxComposeLibraryVersion"
     implementation "androidx.compose.ui:ui:$androidxComposeLibraryVersion"
+    implementation "androidx.compose.ui:ui-unit:$androidxComposeLibraryVersion"
 }
 
 dependencyAnalysis {