Add circle around fret numbers for half notes in tablature

[manolo]

Resolves: #11814 (Half notes to be displayed in circle in TAB staff notation)
Resolves: #13699 (Whole and half notes are not in circle for Common tab staff type)
Related: https://musescore.org/en/node/275196 (Circled fret marks for half note and whole note durations in tablature staves)

Summary

Add a new tablature style option that draws an ellipse around fret numbers for half notes, providing clear visual distinction from other note durations.

Problem

In tablature notation, distinguishing half notes is problematic:

• Short stem: Easily confused with quarter notes
• Slashed stem: Confused with tremolo notation (plucked strings, mandolin)
• No marking: Half notes indistinguishable from whole notes

Prior art

• Guitar Pro/Notion/Scoremaker: Native support
• Sibelius / Finale: Manual workarounds
• The circled fret number is a well-established convention used for years in tablature scores.

Solution

• Adds a new "Circled" option in Staff/Part Properties > Advanced Style Properties.

• Now, tremolo and tempo information is much clearer:

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[manolo]

I guess the failure because of the new test is ok until this is merged.