continuation of #8279
Replaced the blue emergency lights on ambulance vehicles with a new white emergency light item and vehicle part. Added vehicle sprite for the new vehicle part.

Purpose of change (The Why)

Ambulances in the northeast USA use white and red flashing lights, not red and blue lights.

Describe the solution (The How)

Since no white emergency light item existed, a new vehicle part and sprite were added. Previous PR replaced blue lights with red, this PR improves that improvement.

Describe alternatives you've considered

Replacing the blue lights with red lights.

Testing

Tested in-game on a previous save, and a new save and experienced no errors and can see the new item on the spawned ambulance. Ambulances are the only vehicle affected by this change.

Additional context

Checklist

Mandatory

• I wrote the PR title in conventional commit format.
• I ran the code formatter.
• I linked any relevant issues using github keyword syntax like closes #1234 in Summary of the PR so it can be closed automatically.
• I've committed my changes to new branch that isn't main so it won't cause conflict when updating main branch later.