fix(Convert to/from binary data Node): Better mime type defaults (#7693)

Github issue / Community forum post (link here to close automatically):

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/nodes-base/nodes/MoveBinaryData/test/MoveBinaryData.test.ts

@@ -84,6 +84,7 @@ describe('Test Move Binary Data Node', () => {
 										mimeType: 'application/json',
 										fileType: 'json',
 										fileSize: '59 B',
+										fileExtension: 'json',
 									},
 								},
 							},
@@ -103,6 +104,7 @@ describe('Test Move Binary Data Node', () => {
 										fileType: 'json',
 										fileSize: '10 B',
 										fileName: 'example.json',
+										fileExtension: 'json',
 									},
 								},
 							},