[Security Solution] Fix some Prebuilt Rules Cypress tests not running…

… in CI (elastic#191978)

**Resolves: elastic#192256

## Summary

This PR re-enables two Cypress test files that didn't run on CI:
`update_workflow.cy.ts` and `prebuilt_rules_preview.cy.ts`. It also
fixes failing tests in `prebuilt_rules_preview.cy.ts`.

### Changes
- Renamed `update_workflow.ts` -> `update_workflow.cy.ts`. It didn't run
on CI because it wasn't picked up by a glob
[here](https://github.com/elastic/kibana/blob/main/x-pack/test/security_solution_cypress/package.json#L14).
 - `prebuilt_rules_preview.cy.ts`:
- Moved `{ tags: ['@ess', '@serverless'] }` to the top-level `describe`
block instead of having it in a variable that is used in every
`describe`. Apparently the tool we use to parse tags doesn't recognize
tags in variables anymore, so this test didn't run in either ESS or
Serverless pipelines.
- Removed `describe('All environments' ... ` wrappers since they don't
add any value anymore. Didn't remove any actual tests.
- Reverted a change from this
[PR](elastic#181427) that added a
backdrop to the modal which doesn't allow user to switch rules without
closing the modal. We have a
[test](https://github.com/elastic/kibana/blob/main/x-pack/test/security_solution_cypress/cypress/e2e/detection_response/rule_management/prebuilt_rules/prebuilt_rules_preview.cy.ts#L1182)
that checks that such switching is possible and this test started to
fail once I reactivated the test file.
- Fixed selectors that grab filters in the Overview tab. The old ones
stopped working. Probably because of a change to the filters component
that is built by another team.

#### Correct behaviour: Switching between rules with flyout open

https://github.com/user-attachments/assets/da4a0902-657c-45fe-adc1-eb44ad0de798
(cherry picked from commit c65c2ae)

x-pack/plugins/security_solution/docs/testing/test_plans/detection_response/prebuilt_rules/installation_and_upgrade.md

@@ -631,13 +631,9 @@ Given no prebuilt rules are installed in Kibana
 And there are X prebuilt rules of all types available to install
 When user opens the Add Rules page
 Then all X rules available for installation should be displayed in the table
-When user opens the rule preview for the 1st rule
-Then the preview should open
-And all properties of the 1st rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
-When user selects the 2nd rule in the table
-Then the preview should be updated
-And all properties of the 2nd rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
-And user should be able to repeat this for all X rules
+When user opens a rule preview for any rule
+Then the preview should appear
+And all properties of a rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
 ```
 
 #### **Scenario: Tabs and sections without content should be hidden in preview before installing**
@@ -783,15 +779,11 @@ And for all of the installed rules there are new versions available
 And user is on the Rule Management page
 When user opens the Rule Updates table
 Then all X rules available for upgrade should be displayed in the table
-When user opens the rule preview for the 1st rule
-Then the preview should open
+When user opens a rule preview for any rule
+Then the preview should appear
 And the "Updates" tab should be active
 When user selects the "Overview" tab
-Then all properties of the new version of the 1st rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
-When user selects the 2nd rule in the table
-Then the preview should be updated
-And all properties of the new version of the 2nd rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
-And user should be able to repeat this for all X rules
+Then all properties of the new version of a rule should be displayed in the correct tab and section of the preview (see examples of rule properties above)
 ```
 
 #### **Scenario: Tabs and sections without content should be hidden in preview before upgrading**