Remove Outdated and Safe-to-Delete Feature Flags

[Siddhant-K-code]

Description

This PR removes two feature flags which have no code-references:

• publicApiExperimentalWorkspaceService already deleted from ConfigCat dashboard. See (internal conversation)
• showUseLastSuccessfulPrebuild - On in Preview environments (but no code references) & Off in Prod. for Gitpod Cloud (last touched on 2022.10.19) -- Needs to be deleted from Configcat Dashboard after this PR. Also, Related WEB-216

Summary generated by Copilot

🤖 Generated by Copilot at 4f0ab6b

Remove unused feature flags from dashboard query. This simplifies the code and avoids querying unnecessary data.

Related Issue(s)

Fixes #

How to test

Documentation

Preview status

gitpod:summary

Build Options

Build

• /werft with-werft
  Run the build with werft instead of GHA
• leeway-no-cache
• /werft no-test
  Run Leeway with --dont-test

Publish

• /werft publish-to-npm
• /werft publish-to-jb-marketplace

Installer

• analytics=segment
• with-dedicated-emulation
• workspace-feature-flags
  Add desired feature flags to the end of the line above, space separated

Preview Environment / Integration Tests

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-gce-vm
  If enabled this will create the environment on GCE infra
• with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh. If enabled, with-preview and with-large-vm will be enabled.
• with-monitoring

/hold

[filiptronicek]

Thanks!

[Siddhant-K-code]

/unhold