VIEWS : Undefined array key "view_mode"

@coaston , I have fixed the issue please review the patch file

@abhishek_gupta1 Thanks for the patch!

Made one change : setting default instead of NULL when view mode is not available in widget settings.

I have raised MR for the fix. Needs review.

Theres actually a better fix for this and other related tickets that I will push up here in a bit. First off, this formatter needs to have default settings merged in with actual settings and then view_mode will always exist. The bigger underlying issue is in the base formatter as it needs to respond to field changes and serve the default formatter in case the already saved formatter doesn't relate to the field type. I will tag that issue in a separate ticket and link these up but this should resolve all formatter issues.

Addressed in this commit: https://git.drupalcode.org/project/custom_field/-/commit/bc7495df778829b.... You can test latest dev branch to confirm and reopen separate issue if you are still seeing problems but this should be resolved now with the default settings merged in.