[1pt] PR: Fix heal_bridges_osm.py warning

[ZahraGhahremani]

This PR fixes issue #1221. With this the empty DataFrame will not save.

Changes

• heal_bridges_osm.py

Issuer Checklist (For developer use)

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[RobHanna-NOAA]

@ZahraGhahremani : go ahead and merge latest dev into this, then we can likely get Matt or someone else to approve if Carson can't do it before Thurs. That way we can get it in for the merge early next week. :)