fix: Fix erasure of *iterm2* image last column

- fix: Restrict graphics image clear workaround to the *kitty* style
  and *iterm2* style on Konsole.

  - The workaround caused the erasure of the last column of
    iterm2-style images on non-Konsole terminal emulators.

src/termvisage/tui/widgets.py

@@ -9,7 +9,7 @@
 from typing import List, Optional, Tuple
 
 import urwid
-from term_image.image import BaseImage, Size
+from term_image.image import BaseImage, ITerm2Image, KittyImage, Size
 from term_image.utils import get_terminal_name_version, get_terminal_size
 
 from .. import logging
@@ -419,15 +419,25 @@ def content(self, trim_left=0, trim_top=0, cols=None, rows=None, attr_map=None):
 
         fill = b" " * cols
         fill_left = b" " * pad_left
-        fill_right = b" " * pad_right + b"\b " * self._ti_change_state
+        fill_right = b" " * pad_right
+
+        disguise = (
+            b"\b "
+            * self._ti_change_state
+            * (
+                issubclass(tui_main.ImageClass, KittyImage)
+                or issubclass(tui_main.ImageClass, ITerm2Image)
+                and get_terminal_name_version()[0] == "konsole"
+            )
+        )
 
         # Visible padding may be larger than the visible rows
         for _ in range(min(rows, pad_up)):
             yield [(None, "U", fill)]
 
         # See the description of `pad_up` and `pad_down` above
         for line in self.lines[-min(0, pad_up) : min(0, pad_down) or len(self.lines)]:
-            yield [(None, "U", fill_left + line + fill_right)]
+            yield [(None, "U", fill_left + line + fill_right + disguise)]
 
         # Visible padding may be larger than the visible rows
         for _ in range(min(rows, pad_down)):