merge_dims should not throw CRS error when merging "time" with "Lat/Lon/Alt" coordinates

[mpu-creare]

Description
Cannot merge Coordinates, crs mismatch

Steps to Reproduce

ct = podpac.Coordinates([["2000-01-01"]], dims=["time"], crs='EPSG:3758')
cs = podpac.Coordinates([[42], [-72]], ['lat', 'lon'], crs='EPSG:4326')
c = podpac.coordinates.merge_dims([ct, cs])
# thows error

Expected Behavior
Should not throw the error, and c.crs == "EPSG:4326".

Observed Behavior
Throws error