Revert "fix(fields): Implement getClass method"

This reverts commit 6e9d3fe.

Author: gonfunko

plugins/field-bitmap/src/field-bitmap.ts

@@ -640,18 +640,6 @@ export class FieldBitmap extends Blockly.Field<number[][]> {
       );
     }
   }
-
-  /**
-   * Returns this field's class.
-   *
-   * Used by keyboard navigation to look up the rules for navigating from this
-   * field.
-   *
-   * @returns This field's class.
-   */
-  getClass() {
-    return FieldBitmap;
-  }
 }
 
 interface Buttons {

plugins/field-colour/src/field_colour.ts

@@ -728,6 +728,15 @@ export class FieldColour extends Blockly.Field<string> {
     // the static fromJson method.
     return new this(options.colour, undefined, options);
   }
+
+  /**
+   * Returns the class of this field.
+   *
+   * @returns FieldColour.
+   */
+  getClass() {
+    return FieldColour;
+  }
 }
 
 /** The default value for this field. */