Merge #6747

6747: Fix uninitialized `CLineInput` member variables r=def- a=Robyt3

Closes #6745.

## Checklist

- [X] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test (especially base/) or added coverage to integration test
- [ ] Considered possible null pointers and out of bounds array indexing
- [ ] Changed no physics that affect existing maps
- [ ] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: Robert Müller <robytemueller@gmail.com>

src/game/client/lineinput.cpp

@@ -29,11 +29,12 @@ void CLineInput::SetBuffer(char *pStr, size_t MaxSize, size_t MaxChars)
 	m_WasChanged = m_pStr && pLastStr && m_WasChanged;
 	if(!pLastStr)
 	{
+		m_CursorPos = m_SelectionStart = m_SelectionEnd = m_LastCompositionCursorPos = 0;
 		m_ScrollOffset = m_ScrollOffsetChange = 0.0f;
 		m_CaretPosition = vec2(0.0f, 0.0f);
+		m_MouseSelection.m_Selecting = false;
 		m_Hidden = false;
 		m_pEmptyText = nullptr;
-		m_MouseSelection.m_Selecting = false;
 		m_WasRendered = false;
 	}
 	if(m_pStr && m_pStr != pLastStr)