fix(terraform): remove CKV2_AZURE_18 check and improve CKV2_AZURE_1

[gruebel]

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Description

• removed the duplicate check CKV2_AZURE_18
• added support for the new possibility to define the encryption key directly inside the storage account resource

Fixes #5288

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my feature, policy, or fix is effective and works
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules