Adding the link to the E2C migration guide (#79868)
* Adding the link to the E2C migration guide
* Update docs/sources/introduction/grafana-enterprise.md
Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
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Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
(cherry picked from commit e508c83538)
Co-authored-by: Ishan Jain <51803183+ishanjainn@users.noreply.github.com>