Run Manager mixed keyspaces (vnodes + tablets) test on Enterprise Scylla with enlarged (50Gb) dataset

[mikliapko]

Since Scylla Enterprise 2024.2 release, it makes sense to run mixed keyspaces test for Manager with Enterprise release as well.

Also, the dataset used for this test is pretty small (~4Gb) - increased to at least 50Gb to have more tablets generated.

Testing

• [ ] Introduced test

PR pre-checks (self review)

• [x] I added the relevant backport labels
• [x] I didn't leave commented-out/debugging code