Revert "Bump legacy all_packages project AGP version to 7.0.0, Gradle version to 7.0.2 (#6591)"

This reverts commit 080fd74.

Author: auto-submit[bot]

.ci/legacy_project/README.md

@@ -42,11 +42,3 @@ and then deleting everything but `android/` from it:
 - Updates `gradle-wrapper.properties` from `6.7` to `6.7.1`, to add
   support for the Kotlin gradle plugin. If a user runs into this
   error, the error message is clear on how to upgrade.
-- Modifies `build.gradle` to upgrade the Android Gradle Plugin (AGP)
-  from version 4.1.0 to 7.0.0. If a user runs into an error with
-  the AGP version, the warning is clear on how to upgrade
-  the version to one that we support.
-- Modifies `gradle-wrapper.properties` to upgrade the Gradle version
-  from 6.7.1 to 7.0.2. If a user runs into an error with the Gradle
-  version, the warning is clear on how to upgrade the version to
-  one that we support.

.ci/legacy_project/all_packages/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.0.0'
+        classpath 'com.android.tools.build:gradle:4.1.0'
     }
 }
 

.ci/legacy_project/all_packages/android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-all.zip