Fix channels-last portable fallback by inserting explicit dim-order legalization

[arkadip-maitra]

Fixes #16507 #11086

I kept the pass and regressions in separate files to keep the change cleaner. A more optimized followup is probably worth doing if more issues like these appear.

Added separate test file exir/tests/test_legalize_portable_dim_order_pass.py

[pytorch-bot]

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As of commit 392c77a with merge base a6d812a ():

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