Icons for tabs are not displayed

Describe the bug

Icons are absent for different kinds of tabs: task tab, terminal tab, editor tab. Please see https://github.com/eclipse/che/issues/17978#issuecomment-700739292

The issue is blocking an update Devfile E2E tests and GitSSH flow E2E tests #17973.

Che version

• latest
• nightly
• other: please specify

Steps to reproduce

1. Start nightly Eclipse Che
2. Create and open Java maven workspace
3. Open any file, terminal or run a task

Expected behavior

A tab contains the corresponding icon:

Actual wrong result

There are no icons for tabs:

Runtime

• kubernetes (include output of kubectl version)
• Openshift (include output of oc version)
• minikube 1.1.1
• minishift (include output of minishift version and oc version)
• docker-desktop + K8S (include output of docker version and kubectl version)
• other: (please specify)

Screenshots

Installation method

• chectl
  • provide a full command that was used to deploy Eclipse Che (including the output)
  • provide an output of chectl version command
• OperatorHub
• I don’t know

Environment

• my computer
  • Windows
  • Linux
  • macOS
• Cloud
  • Amazon
  • Azure
  • GCE
  • other (please specify)
• other: please specify

Eclipse Che Logs

Additional context

[dmytro-ndp]

@azatsarynnyy

@dmytro-ndp could you also attach the screenshot of Help>About dialog to check what version is used in your case?

It’s nightly version of che-theia: quay.io/eclipse/che-theia@sha256:3be78bf018b54eb6a8cf518a85cda95973cb831652819003e43c234116f3aa05

[dmytro-ndp]

@RomanNikitenko: good catch, thank you!