[4.0] Remove unused fields (#25497)

To the best of my ability to search github these "spacer" were added 57c5180fb5

If you look at that PR the code was wrong and the field was never used althoough it was intended to be a spacer before a button.

That button has long since been removed and has never even been in a 3.x release

Let's stop maintaining it

administrator/components/com_categories/forms/category.xml

@@ -119,12 +119,6 @@
 		<option value="-2">JTRASHED</option>
 	</field>
 
-	<field
-		name="buttonspacer"
-		type="spacer"
-		label="JGLOBAL_ACTION_PERMISSIONS_LABEL"
-	/>
-
 	<field
 		name="checked_out"
 		type="hidden"

administrator/components/com_content/forms/article.xml

@@ -80,11 +80,6 @@
 			multiple="true"
 		/>
 
-		<field
-			name="buttonspacer"
-			type="spacer"
-		/>
-
 		<field
 			name="created"
 			type="calendar"

administrator/components/com_fields/forms/field.xml

@@ -96,12 +96,6 @@
 			<option value="-2">JTRASHED</option>
 		</field>
 
-		<field
-			name="buttonspacer"
-			type="spacer"
-			label="JGLOBAL_ACTION_PERMISSIONS_LABEL"
-		/>
-
 		<field
 			name="checked_out"
 			type="hidden"