Allow agent port to be configurable #14081

Job	Run time
changed_files	12s
towncrier_check	12s
check_if_release_branch	1s
build mirrord CLI	0s
lint	3m 20s
integration_tests	5m 45s
lint_markdown	0s
check-rust-docs	57s
macos_tests	14m 9s
test_agent	3m 19s
test_agent_image	6m 57s
test_cli_image	7m 7s
e2e (docker)	9m 12s
intellij_e2e_on_release_branch	0s
e2e (containerd)	11m 13s
vscode_e2e_on_release_branch	0s
ci	1s
	1h 2m 25s

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