Added a mutually exclusive key and value and updated the functions to work with string and object

[Razen04]

Fixes #9449

Changes made:

1. Added a key and value pair in the osmMutuallyExclusiveTagPairs for crossing=unmarked and crossing_ref=zebra.
2. Updated the way to get pairsFound to handle both string and object.

Before:

There is no warning for crossing_ref=zebra and crossing=unmarked

After:

Now there will be a warning for those specific key=value pairs.