How to run specific Cypress tests with environment variables set on Gitlab?

I do a bunch of automation tests in Cypress. My project CI/CD is on Gitlab. I need to have a possibility to set up environment variable in Gitlab->Pipelines with the list of specific tests which I would like to run ("Test1, Test2"). I added the following to the index.js:

beforeEach(function() {

  const testFilter = Cypress.env('TEST_FILTER');
  if (!testFilter) {
    return;
  }
  
  const testName = Cypress.mocha.getRunner().test.fullTitle();
  cy.log("beforeEach1");
  if (!testName.includes(testFilter)) {
    cy.log("beforeEach2");
    this.skip();
  }
})

Then I updated my .gitlab-ci.yml with:

- TEST_FILTER: sampleTest.feature

And finally I have :

"cy:open": "cypress open",
"cy:filter:implicit": "set CYPRESS_TEST_FILTER=Implicit & cypress open",

However it doesn't work and when I run pipeline and add variable there on Gitlab (TEST_FILTER) I get this error:

Pipeline cannot be run.

Undefined error (01GDMNJ755F2J576MWPPX5Y9QQ)

Could you please help me to understand what I'm doing wrong?