Provide option to choose a environmental variable from list (Choice parameter) while building a pipeline

We can have global environmental variable for a project. however sometimes while manually triggering a pipeline, we need a dropdown list of global environmental variable, as of now I have to paste this somewhere and add it to pipeline while triggering. this is similar to choice parameter feature of Jenkins.

mentioned in issue gitlab-org/quality/triage-reports#1218 (closed)

added automation:ml groupconfigure [DEPRECATED] labels

This issue was automatically tagged with the label ~"group::configure" by TanukiStan, a machine learning classification model, with a probability of 0.03.

If this label is incorrect, please tag this issue with the correct group label as well as automation:ml wrong to help me learn from my mistakes.

added automation:ml wrong grouppipeline execution labels and removed groupconfigure [DEPRECATED] label

Setting label(s) devopsverify sectionops based on ~"group::continuous integration".

added devopsverify sectionops labels

mentioned in issue gitlab-org/quality/triage-reports#1278 (closed)

mentioned in issue gitlab-org/quality/triage-reports#1373 (closed)

changed milestone to %Backlog

added CI variables Category:Continuous Integration labels

added [deprecated] Accepting merge requests label

added grouppipeline authoring label and removed grouppipeline execution label

added 1 deleted label

added typefeature label

added grouppipeline security label and removed grouppipeline authoring label

added Category:Pipeline Composition label

added grouppipeline authoring label and removed grouppipeline security label

added grouppipeline security label and removed Category:Pipeline Composition grouppipeline authoring labels

added Category:Variables grouppipeline authoring sectionci labels and removed grouppipeline security sectionops labels

added Category:Pipeline Composition label