fix(sync-files): keep original source file intact

[xmfcx]

Description

Instead of modifying the source file in place, first copy it to a temp location with mktemp, then do all the modifications and copy to dest path as usual.

Currently it modifies the source files in place.

If multiple versions are to be created from the same source file, it will modify them multiple times, breaking files.

Tests performed

Tested with the temporary v-test-sync-files tag. By calling it from:

• ci: update workflows and sync-files autoware.universe#7340

Without this PR

With this PR

Effects on system behavior

Not applicable.

Interface changes

Pre-review checklist for the PR author

The PR author must check the checkboxes below when creating the PR.

• I've confirmed the contribution guidelines.
• The PR follows the pull request guidelines.

In-review checklist for the PR reviewers

The PR reviewers must check the checkboxes below before approval.

• The PR follows the pull request guidelines.

Post-review checklist for the PR author

The PR author must check the checkboxes below before merging.

• There are no open discussions or they are tracked via tickets.

After all checkboxes are checked, anyone who has write access can merge the PR.