feat: use default config path when no arg for -f is provided #14014

Job	Run time
check_if_release_branch	1s
towncrier_check	8s
changed_files	6s
build mirrord CLI	0s
lint	3m 32s
test_agent	3m 30s
check-rust-docs	1m 3s
integration_tests	13m 29s
macos_tests	24m 12s
test_agent_image	50s
test_cli_image	15m 19s
lint_markdown	0s
vscode_e2e_on_release_branch	0s
intellij_e2e_on_release_branch	0s
e2e (docker)	16m 0s
e2e (containerd)	14m 21s
ci	1s
	1h 32m 32s

Provide feedback