Bump exoplayer_version from 2.18.5 to 2.18.6

Bumps `exoplayer_version` from 2.18.5 to 2.18.6.

Updates `com.google.android.exoplayer:exoplayer-core` from 2.18.5 to 2.18.6
- [Release notes](https://github.com/google/ExoPlayer/releases)
- [Changelog](https://github.com/google/ExoPlayer/blob/release-v2/RELEASENOTES.md)
- [Commits](https://github.com/google/ExoPlayer/compare/r2.18.5...r2.18.6)

Updates `com.google.android.exoplayer:extension-okhttp` from 2.18.5 to 2.18.6
- [Release notes](https://github.com/google/ExoPlayer/releases)
- [Changelog](https://github.com/google/ExoPlayer/blob/release-v2/RELEASENOTES.md)
- [Commits](https://github.com/google/ExoPlayer/compare/r2.18.5...r2.18.6)

---
updated-dependencies:
- dependency-name: com.google.android.exoplayer:exoplayer-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: com.google.android.exoplayer:extension-okhttp
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -6,7 +6,7 @@ buildscript {
         build_tool_version = '33.0.1'
         kotlin_version = '1.8.20'
         agp_version = '8.0.0'
-        exoplayer_version = '2.18.5'
+        exoplayer_version = '2.18.6'
         splitties_version = '3.0.0'
         room_version = '2.5.1'
     }