Fix since value for set_pip_original_window

BUG=None
TEST=compiles

Change-Id: I1a631831f9e9fe61066d483f3ae691bee872c88f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994030Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Kazuki Takise <takise@chromium.org>
Auto-Submit: Kazuki Takise <takise@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732301}

third_party/wayland-protocols/unstable/remote-shell/remote-shell-unstable-v1.xml

@@ -1044,13 +1044,13 @@
     </request>
 
     <!-- Version 26 additions -->
-    <request name="set_pip_original_window" since="25">
+    <request name="set_pip_original_window" since="26">
       <description summary="set the pip original window">
         Set this surface the original window for the current PIP window.
       </description>
     </request>
 
-    <request name="unset_pip_original_window" since="25">
+    <request name="unset_pip_original_window" since="26">
       <description summary="unset the pip original window">
         Unset this surface the original window for the current PIP window.
       </description>