Feature Request: Support grep with regex patterns in searchPaths for Python Environment Tools (PET) integration

[eleanorjboyd]

Building on the work done in microsoft/vscode-python-environments#870 and discussions in microsoft/vscode-python-environments#906, we need to enhance the python-env.workspaceSearchPaths setting to support regular expressions and grep-like pattern matching. The best place to make this change is to do so directly on the Python Environment Tools (PET) on the backend side then support passing through regex from the envs ext as part of the mentioned setting