[MU4 Issue] "Replace instrument" does not change staff type; so no need for tablature options

[rgreen5]

Describe the bug

If you start with, say, a guitar tablature score, and use "Replace instrument" (right-click on staff) you cannot change the tablature to standard staff (or vice versa) even though this possibility seems to be implied by the UI.

For example, you have the option of "Electric Guitar" or "Electric Guitar (tab)" in "Change instruments", but whether you choose one or the other the staff remains the same.

To reproduce

1. Open the attached tablature example. change_instrument_issue.zip
2. Right-click on the staff and choose "Replace instrument".
3. Choose "Electric Guitar".

RESULT: The staff type remains as tablature, even though you might expect this option to return a standard music staff.

Expected behavior

IMV, it is to be expected that "Replace instrument" should not change the staff type. However this should be reflected in the UI of the "Replace instrument" dialog; the tablature options can be omitted since it is only the instrument that changes.

Platform information

OS: Linux Mint 20.1, Arch.: x86_64, MuseScore version (64-bit): 4.0.0-223080420, revision: github-musescore-musescore-2c34155

[Tantacrul]

We want to ultimately do away with the idea of providing different instrument definitions based on the type of staff they use. This is also true for things like 'Violin' VS 'Violins'. We'll need more options in the Add Instruments dialog in a later release of 4.x.