Restore branch and git sha, to use it in logs and in rageshakes.

Remove quite useless `gitRevisionDate`.

libraries/core/src/main/kotlin/io/element/android/libraries/core/meta/BuildMeta.kt

@@ -25,7 +25,6 @@ data class BuildMeta(
     val versionName: String,
     val versionCode: Int,
     val gitRevision: String,
-    val gitRevisionDate: String,
     val gitBranchName: String,
     val flavorDescription: String,
     val flavorShortDescription: String,