Respect editor tab/space settings when parsing formatting prefs used by organize imports

[Copilot]

editor.action.organizeImports was applying default indentation behavior for multiline named imports instead of honoring editor indentation settings. The mismatch came from preference parsing: editor-facing keys were not fully translated into the raw formatting settings consumed by import-edit generation.

• Config parsing: map editor keys to formatting raw keys

  • In ParseUserPreferences, when ingesting the editor section:
    • map insertSpaces → convertTabsToSpaces (when not explicitly provided)
    • map tabSize → indentSize (when not explicitly provided)
  • This aligns organize-import rewrite indentation with editor settings (tabSize / tab-vs-space mode).

• Precedence preserved

  • Alias mapping is non-destructive: explicit raw values in editor config (e.g. convertTabsToSpaces) continue to win over alias-derived values.

• Focused regression coverage

  • Added tests in internal/ls/lsutil/userpreferences_test.go to validate:
    • editor tabSize + insertSpaces correctly populate FormatCodeSettings
    • explicit convertTabsToSpaces overrides insertSpaces alias mapping

// editor -> unstable aliasing used before preference overlay
if tabSize, ok := unstableEditorSettings["tabSize"]; ok {
    if _, hasIndentSize := unstableEditorSettings["indentSize"]; !hasIndentSize {
        unstableEditorSettings["indentSize"] = tabSize
    }
}
if insertSpaces, ok := unstableEditorSettings["insertSpaces"]; ok {
    if _, hasConvertTabs := unstableEditorSettings["convertTabsToSpaces"]; !hasConvertTabs {
        unstableEditorSettings["convertTabsToSpaces"] = insertSpaces
    }
}

• Fixes Organize imports command doesn't respect tabSize/insertSpaces settings #4571

[jakebailey]

This is identical to #4602