[eas-cli] Default update message to `undefined` in no-VCS client

[sjchmiela]

Why

https://staging.expo.dev/accounts/sjchmiela/projects/staging-app/workflows/01932b13-21af-780b-b531-1ed07e3d8228

eas update --auto fails in GCS update job because this flag is set to true.

How

The comment says it can be false, so changed it to false.

https://github.com/expo/eas-cli/pull/2148/files#diff-a594e233350755033d45aa7b21b78781e4b36322e9312f60e71e7edc79c33a7f

Test Plan

Update message should be changed to undefined.

[github-actions[bot]]

Subscribed to pull request	File Patterns	Mentions
**/*	@szdziedzic, @khamilowicz

Generated by CodeMention

[github-actions[bot]]

Size Change: +126 B (0%)

Total Size: 52.9 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	52.9 MB	+126 B (0%)

_{compressed-size-action}

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 52.94%. Comparing base (86c99ef) to head (9799c27). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/eas-cli/src/vcs/clients/noVcs.ts	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2690 +/- ## ======================================= Coverage 52.94% 52.94% ======================================= Files 576 576 Lines 22105 22105 Branches 4337 4337 ======================================= Hits 11701 11701 Misses 10370 10370 Partials 34 34 ```

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[github-actions[bot]]

⏩ The changelog entry check has been skipped since the "no changelog" label is present.