doctype cache is never used

[ankush]

https://github.com/frappe/frappe/blob/ba311a3ec83807f8a07f55e4beac6a09a7108b77/frappe/desk/form/load.py#L73-L74

comparing DateTime with string will always be false.

Also, this whole caching implementation is weird. If request is made and all the cost is paid then what's the point of not sending data back? Few KBs of network i/o saved at max.

NOTE: don't just fix it. Since this never really worked, the implementation is also flaky. Sometimes dependent doc meta is not cached which results in broken forms.

IMO lets just remove this entirely and redo cache implementation.

[sagarvora]

Yes, let's redo JS cache implementation 👍🏼