Infer grid from UxDataArray inputs during UxDataset({"varname": uxarr, ...}) #1886

Proposed new feature or change:

When creating a UxDataset, if any of the input data vars are UxDataArrays, the grid should probably be inferred directly, instead of requiring the user to input it separately.

For example:

import uxarray as ux
arrA = ux.tutorial.open_dataset('quad-hexagon-random-node')['random_data_node']
arrB = ux.tutorial.open_dataset('quad-hexagon-random-face')['random_data_face']
assert arrA.uxgrid == arrB.uxgrid
ds = ux.UxDataset({'A': arrA, 'B': arrB})
ds.uxgrid

I would have wanted ds.uxgrid to be auto-filled as arrA.uxgrid (which is equal to arrB.uxgrid), but instead this crashes with GridInvalidError. To produce the desired result, the user currently needs to explicitly specify ds = ux.UxDataset({'A': arrA, 'B': arrB}, uxgrid=arrA.uxgrid) instead.

Considering this feature in the first place is also what led me to finding a bug: the code currently does not run any checks to confirm that the input UxDataArrays' grids actually match the provided uxgrid. (This bug is being tracked separately; see #1853 (comment)).