coordination #130216: [epic] Adapt migration test coverage and its migration matrix for SLE 15 SP6
Update the flavors of Continuous and Leap migration to ensure triggered automatically for SLE15-SP6
Some migration flavor names designed with service pack version which is not good, such as 'Continuous-Migration-SLE15SP5', should change it to Continuous-Migration-SLE15-SPx for 15SP6, need a MR to update this for IBS auto trigger.
So for 'Migration-from-Leap-15.5-to-SLE15-SP5', changed to 'Migration-from-Leap-15.x-to-SLE15-SPx' for 15-SP6.
AC1: Ensure the two Migration flavors in Migration misc job group are triggered automatically with the OBS Sync mechanism
For continuous migration flavor changed to Continuous-Migration-SLE15-SPx which already fit the requirement for ibs trigger script, so only need update leap migration flavor on ibs. Created MR: https://gitlab.suse.de/openqa/openqa-trigger-from-ibs-plugin/-/merge_requests/140