Do not re-deploy unchanged functions when using --only functions:codebase

### [REQUIRED] Environment info

**firebase-tools:** 12.3.1

**Platform:** any

### [REQUIRED] Test case

Due to this change here: https://github.com/firebase/firebase-tools/pull/4968, a functions deploy will always redeploy all functions when using the --only flag, regardless of whether there are any changes and whether that function was targeted directly.

I believe this could be changed to only force functions to deploy if they were targeted directly via `--only functions:`

### [REQUIRED] Steps to reproduce

- Deploy all functions
- Deploy an unchanged codebase using `--only functions:`

### [REQUIRED] Expected behavior

The unchanged functions within the selected codebase will not be deployed again.

### [REQUIRED] Actual behavior

All functions in the codebase will be re-deployed even if there have not been any changes.