MacOS: Fix focus grab warning on macOS when running game in embedded mode.

[LanzaSchneider]

Fixes focus grab warning on macOS when running game in embedded mode.

Issue

When running a game with "Embed Game on Next Play" enabled on macOS, the following warning is printed:
"This control can't grab focus. Use set_focus_mode() and set_focus_behavior_recursive()
to allow a control to get focus."

Root Cause

EmbeddedProcessMacOS is explicitly configured with set_focus_mode(FOCUS_NONE) in its constructor,
while GameView unconditionally calls grab_focus() on it when starting the game instance.

The focus is intentionally delegated to the child layer_host which uses FOCUS_ALL.
However, grab_focus() on the parent process still triggers the warning even though this
is the intended design on macOS.

Solution

Add a focus mode check before calling grab_focus() in GameView::_play_pressed() and
GameView::_instance_starting(). This prevents the warning when the control is explicitly
set to not accept focus, matching the macOS-specific implementation's design.

Changes Made

• Added if (embedded_process->get_focus_mode_with_override() != FOCUS_NONE) guard
  before embedded_process->grab_focus() calls in game_view.cpp

Testing

• Tested on macOS: warning no longer appears when launching game in embedded mode
• Verified other platforms (Windows/Linux) remain unaffected
• Confirmed focus behavior still works correctly in embedded game window

[akien-mga]

Thanks!