Part of Code Quality Project outlined in #130975.
This patch eschews warning messages urging the user to "select all
related strips" when copying or creating new metastrips and instead
automatically includes those related strips in the operation.
- Attempting to copy or create a metastrip with no strips selected no
longer delivers a warning.
- When copying strip(s), if there are related effect chains, they will
be automatically selected and included in the copy if the operation
succeeds.
- The decision to select related strips was intentional, as it allows
the user to easily see the entire effect chain and thus which strips
were copied.
- When creating a new metastrip, if there are related effect chains,
they will automatically be included in the resulting metastrip.
- This is done using a new
`SEQ_query_strip_connected_and_effect_chain()` iterator. This
iterator is only used for metastrips, and not copying, since the
user may wish to only copy single strips in a connection, but
connected strips should always stay together in a metastrip/seqbase.
Pull Request: https://projects.blender.org/blender/blender/pulls/132930
6ac58a5b8a