[submodule] Update submodule linkmgrd to the latest HEAD automatically (#15654)

mssonicbld · web-flow · commit 14f5f127c9cb · 2023-08-10T16:05:40.000-07:00
#### Why I did it src/linkmgrd ``` * 3f89fce - (HEAD -> 202012, origin/202012) [202012] Use Vlan MAC as src MAC for link prober by default #93 (#209) (6 weeks ago) [Jing Zhang] ```
diff --git a/src/linkmgrd b/src/linkmgrd
@@ -1 +1 @@
-Subproject commit 35f7d1c257b2ec62cb79a5f637c11f2dd9782cbe
+Subproject commit 3f89fcefeb747634e071a5069157e8aaea30d974
