fix: #9998 MkNote.vue, MkNoteDetailed.vue で、特定のMFMによってフッターのボタンが押せなくなる (#9999)

* fix(client): add `overflow: clip;`

* fix(client): add `overflow: clip;`

* Revert "fix(client): add `overflow: clip;`"

This reverts commit c43226afde4741d61088192cbbab09fe97e1f2fb.

Revert "fix(client): add `overflow: clip;`"

This reverts commit c7225151056ff15b953aae806e7a07fa13fab746.

* feat(client): add z-index to .footer

packages/frontend/src/components/MkNote.vue

@@ -484,6 +484,11 @@ function showReactions(): void {
 		}
 	}
 
+	.footer {
+		position: relative;
+		z-index: 1;
+	}
+
 	&:hover > .article > .main > .footer > .footerButton {
 		opacity: 1;
 	}