backported "Create metric button and docs link in empty state" (#48685)

* Create metric button and docs link in empty state (#48468)

* Add 'Create metric' button to empty metrics page

* Add e2e test for 'Create metric' button

* Remove duplicate main on Browse page

* Add docs link

* Split off common test for BrowseMetrics

* Add whitespace

Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>

* Use cy.button

Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>

* Hide Create metric button when the user does not have data access

* Use findByText for link

* Add test for hiding the 'Create metric' button when the user does not have data access

* Fix unit tests

* Improve copy

Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>

* Add whitespace

Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>

* Add explanatory comment for enterprise

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Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>

* Update failing loki test

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Co-authored-by: Romeo Van Snick <romeo@romeovansnick.be>
Co-authored-by: Kamil Mielnik <kamil@kamilmielnik.com>