Remove unused data field file

module/data/fields/EphemeralObjectField.mjs

@@ -1,29 +0,0 @@
-/**
- * This data field functions the same way as Foundry's ObjectField
- * however it permits changes to internal properties to be tracked in
- * a diff, without committing those changes to the database unless it's
- * removing the entire object.
- */
-export class EphemeralObjectField extends foundry.data.fields.ObjectField {
-
-	/**
-	 * Inverting the defaults from ObjectField since we don't want it to
-	 * be stored in the database anyway
-	 */
-	static get _defaults() {
-		return Object.assign(super._defaults, { required: false, nullable: true });
-	};
-
-	/**
-	 * When trying to diff the object, only allow deletions to go through,
-	 * otherwise ignore it entirely
-	 */
-	_updateDiff(key, value, options, state) {
-		if (
-			!value
-			|| (value instanceof foundry.data.operators.ForcedDeletion)
-		) {
-			return super._updateDiff(key, value, options, state);
-		};
-	};
-};