[Core] Add is_oled_scrolling (#14305)

docs/feature_oled_driver.md

@@ -356,6 +356,10 @@ bool oled_scroll_left(void);
 // Returns true if the screen was not scrolling or stops scrolling
 bool oled_scroll_off(void);
 
+// Returns true if the oled is currently scrolling, false if it is
+// not
+bool is_oled_scrolling(void);
+
 // Inverts the display
 // Returns true if the screen was or is inverted
 bool oled_invert(bool invert);