use NE min_zoom for min_zoom on region boundaries

[tgrigsby-sc]

Fixes https://github.com/tilezen/vector-datasource/issues/2062.

This change moves to using the min_zoom field for NE region boundaries, clamped between 3 and 11.

• [X] Update tests
• [ ] Docs (N/A)

[tgrigsby-sc]

• [X] 797 (fixed)
• [ ] 992 (needs updates to test shp files)
• [X] 1970 (not broken)
• [X] 1983 (not broken)