[codex] Disable CLI diff rendering #540

Job	Run time
build-and-smoke-freebuff-windows	2m 51s
build-freebuff	1m 46s
e2e-ads-behavior	1m 30s
e2e-help-command	1m 38s
e2e-slash-commands	1m 15s
e2e-startup	1m 42s
e2e-version	1m 39s
e2e-terminal-command	1m 37s
e2e-code-edit	1m 37s
e2e-agent-startup	2m 56s
	18m 31s

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