GUI: Reduce CPU usage II - have smoother UX with faster refresh rate

* Set thread_sleep_interval to 0.01s for better UI responsiveness
* Improve thread waiting with thread.join() where applicable (thanks to @sbytnar)

opencore_legacy_patcher/wx_gui/gui_macos_installer_flash.py

@@ -3,7 +3,6 @@ gui_macos_installer_flash.py: macOS Installer Flash Frame
 """
 
 import wx
-import time
 import logging
 import plistlib
 import tempfile
@@ -317,7 +316,7 @@ class macOSInstallerFlashFrame(wx.Frame):
             wx.CallAfter(progress_bar.SetValue, bytes_written)
 
             wx.Yield()
-            time.sleep(self.constants.thread_sleep_interval)
+            thread.join(timeout=self.constants.thread_sleep_interval)
 
         if self.result is False:
             logging.error("Failed to flash installer, cannot continue.")

opencore_legacy_patcher/wx_gui/gui_support.py

@@ -273,7 +273,7 @@ def wait_for_thread(thread: threading.Thread, sleep_interval=None):
 
     while thread.is_alive():
         wx.Yield()
-        time.sleep(interval)
+        thread.join(timeout=interval)
 
 
 class RestartHost: