E2E to link a line in Web IDE

Description of the test

E2E test for the new feature of linking to a single line number in Web IDE (introduced in #21762 (closed)).

Scenario: As admin click on link icon to get a sharing url for a specific line in Web IDE -> Different user visits the url -> Gets transferred to the original line in Web IDE.

Testcase issue - gitlab-org/quality/testcases#1102 (closed)

Check-list

• Confirm the test has a testcase: tag linking to an existing test case in the test case project.
• Note if the test is intended to run in specific scenarios. If a scenario is new, add a link to the MR that adds the new scenario.
• Follow the end-to-end tests style guide and best practices.
• Use the appropriate RSpec metadata tag(s).
• Ensure that a created resource is removed after test execution. A Group resource can be shared between multiple tests. Do not remove it unless it has a unique path. Note that we have a cleanup job that periodically removes groups under gitlab-qa-sandbox-group. NB project resources are also deleted by a cleanup job automatically.
• Ensure that no transient bugs are hidden accidentally due to the usage of waits and reloads.
• Verify the tags to ensure it runs on the desired test environments.
• If this MR has a dependency on another MR, such as a GitLab QA MR, specify the order in which the MRs should be merged.
• (If applicable) Create a follow-up issue to document the special setup necessary to run the test: ISSUE_LINK