Terraform v1.15.5 adds module version null support, fixes init crash

Terraform version 1.15.5 introduces support for module versions evaluating to null, specifically within dynamic module sources. This release also addresses a crash encountered during `init` for modules that have an empty source attribute. These changes are relevant for users managing infrastructure with Terraform, particularly those utilizing dynamic module configurations or encountering initialization issues.

• →Support for module version evaluating to null (in the context of dynamic module sources)
• →Fix crash on init for modules with empty source