Fix NoClassDefFoundError exceptions for TermuxActivity

This commit fixes the non-crashing exception `Rejecting re-init on previously-failed class java.lang.Class<androidx.core.view.ViewCompat$2>: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/view/View$OnUnhandledKeyEventListener;` on termux startup due to `setContentView()` call by `TermuxActivity.onCreate()`. The recommended solution seems to be to add `androidx.core:core` dependency, which has solved the issue.

https://issuetracker.google.com/issues/117685087

app/build.gradle

@@ -10,6 +10,7 @@ android {
         implementation "androidx.annotation:annotation:1.1.0"
         implementation "androidx.viewpager:viewpager:1.0.0"
         implementation "androidx.drawerlayout:drawerlayout:1.1.1"
+        implementation 'androidx.core:core:1.5.0-beta02'
         implementation project(":terminal-view")
     }