DEPR: automatic upcasting in reindex

[jbrockmendel]

• closes DEPR: automatic upcasting on invalid reindex fill_value #53910 (Replace xxxx with the GitHub issue number)
• closes EA interface: add maybe_promote? #24246
• closes BUG/Internals: maybe_promote #23833
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

This deprecates Series[int].reindex(..., fill_value=anything_other_than_int_or_nan) following PDEP6-like-logic. Because we have deprecated the analogous behavior in all of the other places where maybe_promote is called, this also closes the two issues about that function.

There is one algos.take_nd call in get_values_for_csv that we'll have to find an alternative for before this is enforced.