"Invalid file type" error not shown in ajax upload.

[aaronfc]

Describe the bug
When a file with an invalid type is selected in a file input while ajax upload is enabled the file is ignored but no feedback is shown to the user.

To Reproduce
Steps to reproduce the behavior:

1. Go to submit a job.
2. Select an incorrect file (anything which is not an image) when uploading the company logo.

Screenshots

Expected behavior
Some feedback should be shown to the user. Other similar errors like when a file is too big are displayed with a simple window.alert.

Isolating the problem (mark completed items with an [x]):

• I have deactivated other plugins and confirmed this bug occurs when only WP Job Manager plugin is active.
• This bug happens with a default WordPress theme active.
• I can reproduce this bug consistently using the steps above.

WordPress Environment

• WordPress Version: 5.9.1
• WP Job Manager Version: 0486584
• PHP Version: 7.4.1
• Other important details: We have a tutorial explaining how to limit the file types allowed during upload here.

[Hastibe]

Thanks for creating this bug report, @aaronfc -- we've noticed this, too, and have had users confused by it, so having an error thrown for the user when they attempt to add an invalid file type as the logo would be helpful.