Sorting by channel ascending or descending does not sort experiments correctly

[SoftVision-CiprianMuresan]

[Affected versions]:

• Firefox Release 65.0.2 and above

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

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

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to "https://experimenter.stage.mozaws.net/".
2. Click the "Sort Experiments" drop down and select the "Firefox Channel Ascending" option.
3. Scroll down the page and observe the experiment channels.
4. Repeat Step 3 for all pages.

[Expected result]:

• Experiments are ordered in the following way Firefox - Release Firefox - Beta Firefox - Nightly Firefox.
  OR
• Experiments are ordered in the following way Nightly Firefox - Beta Firefox - Release Firefox - Firefox.

[Actual result]:

• Experiments are ordered in the following way Firefox - Beta Firefox - Nighty Firefox - Release Firefox.

[Notes]:

• The issue is reproducible with the "Firefox Channel Descending" option as well, but in this case the order is Release - Nightly - Beta - Firefox.
• Attached is a screen recording of the issue: Link

[Softvision-RemusDranca]

I have verified this issue and is no longer reproducible on Experimenter stage "https://stage.experimenter.nonprod.dataops.mozgcp.net" website after the v2.28.0 stage deployment.
Tested on Windows 10x64, Mac 10.14 and Arch Linux 4.16.6 x64.