[KBM] Fix modifier key remapped to non-modifier delivering WM_SYSKEYDOWN (#47192)

## Summary of the Pull Request

When a modifier key (Ctrl/Alt/Shift) is remapped to a non-modifier key
using
Keyboard Manager, the injected key event is delivered to applications as
WM_SYSKEYDOWN instead of WM_KEYDOWN. This causes unexpected behavior —
for
example, remapping Left Alt to Backspace results in whole words being
deleted
instead of single characters, because applications interpret
WM_SYSKEYDOWN +
VK_BACK as Alt+Backspace.

The fix resets the modifier state with a suppress-flag key-up event
before
injecting the target key, consistent with the existing approach used for
the
Caps Lock remapping scenario.

## PR Checklist

- [ ] Closes: #47191
- [ ] Communication: I've discussed this with core contributors already.
If the work hasn't been agreed, this work might be rejected
- [x] Tests: Added/updated and all pass
- [ ] Localization: All end-user-facing strings can be localized
- [ ] Dev docs: Added/updated
- [ ] New binaries: Added on the required places

## Detailed Description of the Pull Request / Additional comments

The root cause is that SendInput is called inside the low-level keyboard
hook
callback before the original modifier event is suppressed. At that point
the
modifier state is still active, so the OS delivers the injected key as
WM_SYSKEYDOWN (system key with Alt context) rather than WM_KEYDOWN.

This is the same mechanism that was already fixed for the Ctrl/Alt/Shift
↔
Caps Lock case. This PR extends the fix to cover modifier → non-modifier
remaps.

## Validation Steps Performed

1. Remapped Left Alt → Backspace in Keyboard Manager
2. Opened a text editor, typed text, pressed the remapped key
3. Confirmed single characters are deleted instead of whole words
4. All 93 unit tests pass (KeyboardManager.Engine.UnitTests)

src/modules/keyboardmanager/KeyboardManagerEngineLibrary/KeyboardEventHandlers.cpp

@@ -139,6 +139,14 @@ namespace KeyboardEventHandlers
                 if (data->wParam == WM_KEYDOWN || data->wParam == WM_SYSKEYDOWN)
                 {
                     ResetIfModifierKeyForLowerLevelKeyHandlers(ii, it->first, target);
+
+                    // If a Ctrl/Alt/Shift key is remapped to a non-modifier key, reset the modifier state to prevent the injected key from being delivered as WM_SYSKEYDOWN instead of WM_KEYDOWN
+                    if (Helpers::IsModifierKey(it->first) && !Helpers::IsModifierKey(target) && target != VK_CAPITAL && !(it->first == VK_LWIN || it->first == VK_RWIN || it->first == CommonSharedConstants::VK_WIN_BOTH))
+                    {
+                        std::vector<INPUT> suppressList;
+                        Helpers::SetKeyEvent(suppressList, INPUT_KEYBOARD, static_cast<WORD>(it->first), KEYEVENTF_KEYUP, KeyboardManagerConstants::KEYBOARDMANAGER_SUPPRESS_FLAG);
+                        ii.SendVirtualInput(suppressList);
+                    }
                 }
 
                 if (remapToKey)