Allow for HighlightNeighbors on Mobile

This isn't a perfect implementation, but it does allow for tap+hold to
highlight neighbors on mobile.

Shortcomings:
- When releasing a "long press", neighbors will not be revealed, as is
  the case on desktop. So, have to release the long press and then do
  another short press / tap to do the Reveal Neighbors action.

app/javascript/controllers/games/current/board/cell.js

@@ -28,6 +28,8 @@ class Cell {
   }
 
   dehighlightNeighbors(url) {
+    if (this.isNotRevealed || this.isBlank) return
+
     this.#submit(url)
   }
 

app/javascript/controllers/games/current/board_controller.js

@@ -90,6 +90,8 @@ export default class extends Controller {
     if (this.isDesktop) return
     this.longPressExecuted = this.touchMoveDetected = false
 
+    cell(event.target).highlightNeighbors(this.highlightNeighborsUrlValue)
+
     this.longPressTimer = touch(event).onLongPress(() => {
       this.longPressExecuted = true
       this.#longPress(event)
@@ -104,7 +106,10 @@ export default class extends Controller {
 
   dispatchTouchEnd(event) {
     if (this.isDesktop) return
-    if (this.touchMoveDetected || this.longPressExecuted) return
+    if (this.touchMoveDetected || this.longPressExecuted) {
+      cell(event.target).dehighlightNeighbors(this.dehighlightNeighborsUrlValue)
+      return
+    }
 
     clearTimeout(this.longPressTimer)
     this.#tap(event)