build: update AndroidX activity/fragments and resolve compile failure

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

build.gradle

@@ -1,6 +1,6 @@
 buildscript {
     ext {
-        activityVersion = '1.2.0-alpha07'
+        activityVersion = '1.2.0-beta01'
         agpVersion = '4.0.1'
         annotationsVersion = '1.1.0'
         appcompatVersion = '1.2.0'
@@ -13,7 +13,7 @@ buildscript {
         coroutinesVersion = '1.3.9'
         datastoreVersion = '1.0.0-alpha01'
         desugarVersion = '1.0.10'
-        fragmentVersion = '1.3.0-alpha07'
+        fragmentVersion = '1.3.0-beta01'
         jsr305Version = '3.0.2'
         junitVersion = '4.13'
         kotlinVersion = '1.4.10'

gradle.properties

@@ -18,9 +18,6 @@ org.gradle.jvmargs=-Xmx1536m
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
 
-# R8 Full mode
-android.enableR8.fullMode=true
-
 # https://jakewharton.com/increased-accuracy-of-aapt2-keep-rules/
 android.useMinimalKeepRules=true