Bump kotlin version in multiple_flutters benchmark test (flutter#111521)

Author: camsim99

dev/benchmarks/multiple_flutters/android/app/src/main/AndroidManifest.xml

@@ -12,6 +12,7 @@ found in the LICENSE file. -->
         android:supportsRtl="true"
         android:theme="@style/Theme.MultipleFlutters">
         <activity
+            android:exported="true"
             android:name=".MainActivity"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"

dev/benchmarks/multiple_flutters/android/build.gradle

@@ -4,13 +4,13 @@
 
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = "1.4.32"
+    ext.kotlin_version = "1.7.10"
     repositories {
         google()
         mavenCentral()
     }
     dependencies {
-        classpath "com.android.tools.build:gradle:4.1.2"
+        classpath "com.android.tools.build:gradle:7.3.0"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong

dev/benchmarks/multiple_flutters/android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Jan 27 11:54:04 PST 2021
+#Tue Sep 27 5:06 AM PST 2022
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-all.zip