fix(deps): Downgrade AGP to 8.4.2

Can't sync project on Intellij IDEA. This also doesn't sync on stable
release (see REF 5), they only fix AGP support on major updates.

Thanks JetBrains, for the pain.

REF:
[1] https://youtrack.jetbrains.com/issue/FL-23919
[2] https://youtrack.jetbrains.com/issue/IDEA-348937/2024.1-Beta-missing-option-to-enable-sync-with-future-AGP-versions
  "Ignore AGP compatibility check" option is removed.
[3] https://youtrack.jetbrains.com/issue/IDEA-354790/Android-Plugin-Add-supported-Android-Gradle-Plugin-to-its-description
  This "ignore check" option removal especially annoying for
  multiplatform devs. It's even more annoying when you paid for Ultimate
  Edition yet your work is being blocked by a plugin that works
  perfectly on a free version of similar but striped down edition of
  your IDE.
[4] https://youtrack.jetbrains.com/issue/IDEA-355137/Support-Android-Gradle-plugin-8.5.0
  It's been 7 months, we still stuck on AGP 8.2, amazing.
[5] https://youtrack.jetbrains.com/issue/IDEA-352815/Android-Gradle-Plugin-8.4.0-isnt-supported
  We did get AGP 8.4.x on EAPs for 2024.2, but like... why? why can't
  just do it for 2024.1? this has been an issue for a very long time where
  the AGP support is fixed on EAP for a major update, almost screw up my
  deadline one time, I love Kotlin, but my god this AGP stuff is just
  frustrating.

gradle/androidx.versions.toml

@@ -1,6 +1,6 @@
 [versions]
 activity = "1.9.0"
-agp = "8.5.0"
+agp = "8.4.2"
 lifecycle = "2.8.1"
 
 [libraries]