Remove usage stats for reusable blocks that are removed

When a reusable block is deleted, remove that block from recentInserts
and frequentInserts.

editor/store/reducer.js

@@ -12,6 +12,7 @@ import {
 	first,
 	last,
 	omit,
+	omitBy,
 	without,
 	mapValues,
 	findIndex,
@@ -541,6 +542,16 @@ export function preferences( state = PREFERENCES_DEFAULTS, action ) {
 					},
 				};
 			}, state );
+		case 'REMOVE_REUSABLE_BLOCK':
+			const { id } = action;
+			return {
+				...state,
+				recentInserts: reject( state.recentInserts, ( { ref } ) => ref === id ),
+				insertFrequency: omitBy( state.insertFrequency, ( frequency, key ) => {
+					const { ref } = JSON.parse( key );
+					return ref === id;
+				} ),
+			};
 		case 'TOGGLE_FEATURE':
 			return {
 				...state,

editor/store/test/reducer.js

@@ -1055,6 +1055,37 @@ describe( 'state', () => {
 			} );
 		} );
 
+		it( 'should remove usage stats for reusable blocks that are removed', () => {
+			const initialState = {
+				recentInserts: [
+					{ name: 'core/paragraph' },
+					{ name: 'core/block', ref: 123 },
+					{ name: 'core/block', ref: 456 },
+				],
+				insertFrequency: {
+					[ JSON.stringify( { name: 'core/paragraph' } ) ]: 4,
+					[ JSON.stringify( { name: 'core/block', ref: 123 } ) ]: 2,
+					[ JSON.stringify( { name: 'core/block', ref: 456 } ) ]: 2,
+				},
+			};
+
+			const state = preferences( deepFreeze( initialState ), {
+				type: 'REMOVE_REUSABLE_BLOCK',
+				id: 123,
+			} );
+
+			expect( state ).toEqual( {
+				recentInserts: [
+					{ name: 'core/paragraph' },
+					{ name: 'core/block', ref: 456 },
+				],
+				insertFrequency: {
+					[ JSON.stringify( { name: 'core/paragraph' } ) ]: 4,
+					[ JSON.stringify( { name: 'core/block', ref: 456 } ) ]: 2,
+				},
+			} );
+		} );
+
 		it( 'should toggle a feature flag', () => {
 			const state = preferences( deepFreeze( { features: { chicken: true } } ), {
 				type: 'TOGGLE_FEATURE',