[GHA]: Pull Request check for multiple new data sources/resources

### Description

Generally Pull Requests to the Terraform AWS Provider should never include more than one new data source or resource. Add a PR check to look for this and fail if multiple are found. 

### Affected Resource(s) and/or Data Source(s)

_No response_

### Potential Terraform Configuration

_No response_

### References

_No response_

### Would you like to implement a fix?

None