fix: Google Services Gradle Plugin version check failure

[erisu]

Motivation and Context

fixes: #1284

Build failure when Google Services Gradle Plugin is enabled. It fails because the version checking is calling a variable that was refactored and forgotten.

Description

Changed old variable name gradlePluginGoogleServicesVersion to new variable name cordovaConfig.GRADLE_PLUGIN_GOOGLE_SERVICES_VERSION

Testing

• npm t

Checklist

• I've run the tests to see all new and existing tests pass

[codecov-commenter]

Codecov Report

Merging #1287 (6d39d63) into master (6081cc7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1287   +/-   ##
=======================================
  Coverage   73.25%   73.25%           
=======================================
  Files          21       21           
  Lines        1645     1645           
=======================================
  Hits         1205     1205           
  Misses        440      440           

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[pataar]

After applying this fix, I'm still getting errors related to the google-services plugin.

edit: Bumping to com.google.gms:google-services:4.3.8 worked

[erisu]

@pataar

The error your reporting has nothing to do with the version that is set as default nor the flag is being fixed in this PR.

A plugin that your using appears to require a different version and causing your issues. You should review the plugin requirements and set the version based off what the plugin is requesting.

When I tested the changes from this PR, the Google Services Gradle plugin classpaths is checked out successfuly and builds successfully.

[pataar]

@erisu Yes, upgrading the plugin worked.
Made an issue here: havesource/cordova-plugin-push#108