Update dependency org.jetbrains.kotlin:kotlin-gradle-plugin to v2

Author: renovate[bot]

android/build.gradle

@@ -6,7 +6,7 @@ buildscript {
         minSdkVersion = 21
         compileSdkVersion = 34
         targetSdkVersion = 34
-        kotlinVersion = '1.6.10'
+        kotlinVersion = '2.1.21'
         // react-native-inappbrowser-reborn was using a 1.+ which pulled in an alpha which is very bad
         // - we will want to upgrade to 1.5.0 when we support minsdk 33
         // - we can delete this when inappbrowser-reborn changes their build script to avoid this pattern