[backport#16383 3/3] tests: functional watch-only wallet tests

Summary:
These test the new watch-only defaults for rpcs with include_watchonly
and includeWatching options.

Signed-off-by: William Casarin <jb55@jb55.com>

https://github.com/bitcoin/bitcoin/pull/16383/commits/72eaab073bc747425fe551777154b13a6c4c37c9

doc: add release note for include_watchonly default changes

Signed-off-by: William Casarin <jb55@jb55.com>

https://github.com/bitcoin/bitcoin/pull/16383/commits/72ffbdc5799c1707ecad674d701b43fb80b031d0

Depends on D7122

Concludes backport of Core PR16383

Test Plan:

ninja check check-functional

Reviewers: #bitcoin_abc, deadalnix

Reviewed By: #bitcoin_abc, deadalnix

Subscribers: deadalnix

Differential Revision: https://reviews.bitcoinabc.org/D7123