Downgrade roboelectric to 4.5.1 to fix build until AGP 7.

See
1. https://github.com/robolectric/robolectric/issues/6521
2. https://issuetracker.google.com/issues/159151549

app/build.gradle

@@ -245,7 +245,7 @@ dependencies {
     testImplementation "androidx.test.ext:junit-ktx:1.1.3"
     testImplementation "androidx.test:core-ktx:1.4.0"
     testImplementation "androidx.arch.core:core-testing:2.1.0"
-    testImplementation "org.robolectric:robolectric:4.6"
+    testImplementation "org.robolectric:robolectric:4.5.1"
     testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.5.0'
 
     androidTestImplementation 'org.junit.jupiter:junit-jupiter:5.7.2'