fix: accessibility improvements

Set role of math-filed to "textbox math" since some browsers are not recognizing the the web component.

Also, setting cell drag handles to aria role of none since the functionality is duplicated by the move up and move down buttons for each cell.

src/Cell.svelte

@@ -172,6 +172,7 @@
       </IconButton>
     </span>
     <span
+      role="none"
       class="handle button-container"
       on:mousedown={startDrag}
       on:touchstart|nonpassive={startDrag}
@@ -196,6 +197,7 @@
   <!-- The static element action to select is cell is made available through the keyboard shortcuts
        of Ctrl+ArrowUp and Ctrl+ArrowDown -->
   <!-- svelte-ignore a11y-click-events-have-key-events -->
+  <!-- svelte-ignore a11y-no-static-element-interactions -->
 
   <div
     class="content" class:selected

src/DropOverlay.svelte

@@ -34,6 +34,7 @@
      The overlay contains instructions for how to dismiss by either pressing escape or clicking
      the overlay -->
 <!-- svelte-ignore a11y-click-events-have-key-events -->
+<!-- svelte-ignore a11y-no-static-element-interactions -->
 <div 
   class="drop-overlay"
 	on:drop|preventDefault

src/MathField.svelte

@@ -202,8 +202,12 @@
 
 </style>
 
+<!-- Suppressing some Svelte A11y warnings since math-field is not recognized as an interactive element -->
+<!-- svelte-ignore a11y-no-static-element-interactions -->
+<!-- svelte-ignore a11y-interactive-supports-focus -->
 
 <math-field
+  role="textbox math"
   min-font-scale=0.75
   on:focusin={handleFocusIn}
   on:focusout={handleFocusOut}