Comments can wrongly be saved if only empty spaces are inserted in the input field

[Softvision-RemusDranca]

[Affected versions]:

• Firefox Release 65.0.2 and above
• Chrome 72.0.3626.121

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• You are logged with your LDAP account on the "https://experimenter.stage.mozaws.net/" website.
• Have an experiment created on the Experimenter stage website.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to "https://experimenter.stage.mozaws.net/".
2. Open the created experiment from prerequisites.
3. Click the "+ Add Comment" button from the "Overview" section.
4. Insert an empty space in the input field.
5. Click the "Save Comment" button and observe the behavior.

[Expected result]:

• The "Please fill out this field" message is displayed.

[Actual result]:

• The comment is saved but not validated.

[Notes]:

• This issue is reproducible for all the sections where the "Add comment" option is available.
• Attached is a screen recording of the issue:

[shell1]

it's not saving in Stage, so no longer reproducable. I'm almost OK if this happens once in a while too.

[Softvision-RemusDranca]

I have verified this issue and is no longer reproducible on Experimenter stage "https://stage.experimenter.nonprod.dataops.mozgcp.net/" website. Tested on Windows 10 x64, Mac 10.14 and Arch Linux 4.16.6 x64.