DEV - Darken parts of the map that you can't interact with

### Dependency
- [x] https://github.com/hackforla/311-data/issues/1305#issuecomment-2646473445
- [x] https://github.com/hackforla/311-data/issues/1948
- [x] https://github.com/hackforla/311-data/issues/1861
- [x] ~https://github.com/hackforla/311-data/issues/1982~
- we've obtained relevant definitions, don't need to wait for ticket to close

### Overview
We need to make a visual distinction between Neighborhood Councils (NCs) and other cities, land, and unincorporated areas, since users are getting confused why they are unable to select these non-NC areas of the map.

### Action Items
- [ ] to be determined once design work is complete

### Resources/Instructions
- https://docs.mapbox.com/help/tutorials/create-a-custom-style/

Click To Reveal Instructions On Finding "Dead Zones"

From #1861 ...

Steps to reproduce the behavior:
1. Find Lynwood, to the left find Willowbrook. North west of Willowbrook there is a long section that does not highlight.
2. Find Huntington Park, to the bottom left find Florence-Graham. Directly left is a square that does not highlight.

Image from #1861 which showcase "dead-zone"