fix gradle config to inherit values from parent project using safextget

[shamilovtim]

🔹 JIRA Ticket(s) if any

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✏️ Description

Please provide a brief description of what this pull request does.

Currently we are having to patch the plugin because the gradle build config is hardcoding values rather than inheriting them from the parent project. I applied the standard safeExtGet code popular in most gradle configs to inherit the parent values with a fallback. Otherwise user's projects will error out due to the hardcoding and users must patch the plugin to keep building.

[shamilovtim]

What's it take to merge this? @roninopf

[shamilovtim]

@evangreer91 could you please merge this? It's harmless and would eliminate a patch file for us.