regex validator support for negative MatchString

### Terraform CLI and Framework Versions

TF: 1.7.5
framework: 0.12.0

### Use Cases or Problem Statement

Since golang doesn't support lookahead and lookbehind regular expressions, it would be easier to have a solution in `stringvalidator` package for negative regex match. For example:
Validation to match any string that does not start with `GITHUB_`. Usually it is done with negative lookahead but `golang` does not support it. TF Framework only supports "match" pattern but there is no function provided o work with elimination or strings that don't match a pattern.

### Proposal

New `RegexNotMacthes` function could be defined in `stringvalidator` package so that it approves a string that does not match a given regex pattern.

### Additional Information

_No response_

### Code of Conduct

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