[CT-551] Extra scrubbing for git clone exceptions

[jtcohen6]

Despite the fix in #4507, we're still seeing raw secrets in some exceptions, especially when dbt-core is invoked as a Python module.

• We should look to scrub the contents of CommandResultError (cmd, stdout, stderr), since this can appear in exception tracebacks
• We might want to add a few duplicative layers? Better safe than sorry?

dbt-core/core/dbt/clients/system.py

Line 434 in d1ae9dd

raise dbt.exceptions.CommandResultError(cwd, cmd, proc.returncode, out, err)

dbt-core/core/dbt/clients/git.py

Lines 30 to 31 in d1ae9dd

	def _raise_git_cloning_error(repo, revision, error):
	stderr = error.stderr.decode("utf-8").strip()