R8 configuration doesn't optimize app

Your default current [R8 configuration](https://github.com/element-hq/element-x-android/blob/cbbd0ff079c8950bd4b76db22f7f878f80906a45/app/build.gradle.kts#L136C1-L137C1) does NOT optimize your application.
Instead of `proguard-android.txt` use `proguard-android-optimize.txt`

The [custom configuration](https://github.com/element-hq/element-x-android/blob/develop/app/proguard-rules.pro) keeps several wide namespaces [here](https://github.com/element-hq/element-x-android/blob/develop/app/proguard-rules.pro#L47-L53) and [here](https://github.com/element-hq/element-x-android/blob/develop/app/proguard-rules.pro#L10-L14), which should possibly replaced with narrower rules.

/cc @yncyrydybyl