Fix #27279: Preserve accidental brackets when copying and pasting

[shnCanos]

add optional bracket parameter to Score::changeAccidental

update related Score::changeAccidental call

add unit test "changeAccidentalWithBracket"

Resolves: #27279

Cause of the bug

From what I could gather, an accidental is added to a note in two steps:

• Score::changeAccidental is called and changes the tpc
• Later, Note::updateAccidental is called, looks at the tpc, determines that an accidental is required and adds it accordingly

Since the accidental is computed from the ground up, Note::updateAccidental, doesn’t have enough information to determine whether or not it had brackets, leading to the bug.

Fix

Simply force-add the accidental directly in the Score::changeAccidental with the brackets.

Notes

• I added the brackets as an optional argument because the function was called in other places without a known bracket.

• I only added the bracket argument in the call that lead to the bug.

• I added a default argument so as to change as little code as possible, but simply adding std::nullopt to all the calls is also a choice.

• I signed the CLA

• The title of the PR describes the problem it addresses

• Each commit's message describes its purpose and effects, and references the issue it resolves

• If changes are extensive, there is a sequence of easily reviewable commits

• The code in the PR follows the coding rules

• There are no unnecessary changes

• The code compiles and runs on my machine, preferably after each commit individually

• I created a unit test or vtest to verify the changes I made (if applicable)