ANDROID: Use gradle 6.7 and plugin 4.1.0

Also remove ndk.dir from local.properties since it is getting deprecated

Gradle will only use the info (ndkVersion) in gradle.build. Possibly ndkPath too, but we probably don't need that, since ndk is within the sdk folder (default location)

backends/platform/android/android.mk

@@ -26,7 +26,6 @@ $(PATH_BUILD_GRADLE): $(GRADLE_FILES) | $(PATH_BUILD)
 	$(ECHO) "android.useAndroidX=true\n" >> $(PATH_BUILD)/gradle.properties
 	$(ECHO) "android.enableJetifier=true\n" >> $(PATH_BUILD)/gradle.properties
 	$(ECHO) "sdk.dir=$(realpath $(ANDROID_SDK_ROOT))\n" > $(PATH_BUILD)/local.properties
-	$(ECHO) "ndk.dir=$(realpath $(ANDROID_NDK_ROOT))\n" >> $(PATH_BUILD)/local.properties
 
 $(PATH_BUILD_ASSETS): $(DIST_FILES_THEMES) $(DIST_FILES_ENGINEDATA) $(DIST_FILES_NETWORKING) $(DIST_FILES_VKEYBD) $(DIST_FILES_DOCS) $(PORT_DISTFILES) | $(PATH_BUILD)
 	$(INSTALL) -d $(PATH_BUILD_ASSETS)

dists/android/build.gradle

@@ -4,7 +4,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.0.1'
+        classpath 'com.android.tools.build:gradle:4.1.0'
     }
 }
 

dists/android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip