[Test] Fix broken test on master

[chrisronline]

Fixes broken test introduced by #21491

Test failure:

 14:23:26    │ proc  [ftr]            └- ✖ fail: "apis xpack_main Settings /api/settings with trial license clusters should load multiple clusters"
14:23:26    │ proc  [ftr]            │       
14:23:26    │ proc  [ftr]            │         Error: expected false to sort of equal true
14:23:26    │ proc  [ftr]            │         + expected - actual
14:23:26    │ proc  [ftr]            │       
14:23:26    │ proc  [ftr]            │         -false
14:23:26    │ proc  [ftr]            │         +true

[nreese]

How did #21491 ever get a green CI?

[tylersmalley]

No clue. That PR has only been merged into master and we're working on not regressing the API 6.x. So this doesn't need backported.

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request