Remove dead MasterRefresh code

[mark-sil]

XmlDocConfigureDlg.MasterRefreshRequired has no assignment, so removed the related code.

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This change is 

[github-actions]

NUnit Tests

    1 files  ±0      1 suites  ±0   10m 4s ⏱️ - 1m 4s
4 313 tests ±0  4 240 ✅ ±0  73 💤 ±0  0 ❌ ±0 
4 322 runs  ±0  4 249 ✅ ±0  73 💤 ±0  0 ❌ ±0 

Results for commit 1b257d8. ± Comparison against base commit e3ce5ba.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 33.04%. Comparing base (e3ce5ba) to head (1b257d8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1032      +/-   ##
==========================================
- Coverage   33.04%   33.04%   -0.01%     
==========================================
  Files        1202     1202              
  Lines      278313   278301      -12     
  Branches    37188    37185       -3     
==========================================
- Hits        91968    91962       -6     
+ Misses     158491   158486       -5     
+ Partials    27854    27853       -1     

Files with missing lines	Coverage Δ
Src/xWorks/RecordDocView.cs	0.00% <ø> (ø)
Src/xWorks/XmlDocConfigureDlg.cs	8.27% <ø> (ø)
Src/xWorks/XmlDocView.cs	5.60% <ø> (+0.02%)	⬆️

... and 2 files with indirect coverage changes

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