chore(NODE-3521): find/agg cursor session always there

Author: durran

src/cursor/find_cursor.ts

@@ -68,7 +68,7 @@ export class FindCursor<TSchema = Document> extends AbstractCursor<TSchema> {
   }
 
   /** @internal */
-  _initialize(session: ClientSession | undefined, callback: Callback<ExecutionResult>): void {
+  _initialize(session: ClientSession, callback: Callback<ExecutionResult>): void {
     const findOperation = new FindOperation(undefined, this.namespace, this[kFilter], {
       ...this[kBuiltOptions], // NOTE: order matters here, we may need to refine this
       ...this.cursorOptions,

test/unit/cursor/find_cursor.test.js

@@ -12,7 +12,7 @@ const test = {};
 describe('Find Cursor', function () {
   describe('#next', function () {
     afterEach(function () {
-      mock.cleanup()
+      mock.cleanup();
     });
     beforeEach(function () {
       return mock.createServer().then(mockServer => {