feat(driver): add escape to the pressKey surface

escape is a key a spec has real use for and no platform could send it. android maps it to KEYCODE_ESCAPE, the ios companion to HID usage 41 and the in-simulator runner to XCUIKeyboardKey.escape, and the Key union accepts it so it can be written at all.

internal/driver/ioscompanion/transport/transport.go

@@ -58,7 +58,7 @@ type TextEditor interface {
 	// EraseText deletes characterCount characters from the focused field.
 	EraseText(ctx context.Context, characterCount int) error
 
-	// PressKey presses the named logical key (currently only return/enter).
+	// PressKey presses the named logical key (return/enter and escape).
 	PressKey(ctx context.Context, key string) error
 }