CSPL-3534 Fixing string processing in cluster script

[kasiakoziol]

Description

This PR fixes string processing of the AWS policy for creating a cluster setup. Previously, running the policy related command in the terminal resulted in an incorrect output.

Key Changes

Changing $variable to ${variable}.

Testing and Verification

Running the policy related command in a local setup resulted in a correct input. This is a helper script and doesn't require writing or updating automated tests.

Related Issues

Github issue: https://splunk.atlassian.net/browse/CSPL-3534

PR Checklist

• Code changes adhere to the project's coding standards.
• Relevant unit and integration tests are included.
• Documentation has been updated accordingly.
• All tests pass locally.
• The PR description follows the project's guidelines.

[coveralls]

Pull Request Test Coverage Report for Build 13816771271

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 86.59%

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Totals
Change from base Build 13805933276:	0.008%
Covered Lines:	10538
Relevant Lines:	12170

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 13816771275

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.008%) to 86.59%

---

Totals
Change from base Build 13805933276:	0.008%
Covered Lines:	10538
Relevant Lines:	12170

---

💛 - Coveralls