Upgrade to gradle 6.9.4 to leverage fix and optimizations in gradle build

[hydraxman]

Linked GitHub issue ID: #

Pull Request Checklist

• Tests for the changes have been added (for bug fixes / features)
• Code compiles correctly with all tests are passed.
• I've read the contributing guide and followed the recommended practices.
• Wikis or README have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

If this introduces a breaking change for Hydra Lab users, please describe the impact and migration path.

• Yes
• No

Pull Request Description

A few words to explain your changes: Upgrade to gradle 6.9.4 to leverage fix and optimizations in gradle build

How you tested it

Please make sure the change is tested, you can test it by adding UTs, do local test and share the screenshots, etc.

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Technical design
• Build related changes
• Refactoring (no functional changes, no api changes)
• Code style update (formatting, renaming) or Documentation content changes
• Other (please describe):

Feature UI screenshots or Technical design diagrams

If this is a relatively large or complex change, kick it off by drawing the tech design with PlantUML and explaining why you chose the solution you did and what alternatives you considered, etc...