Remove GraphQL field `hasSolutions` from VulnerabilityType

Why are we doing this work

In Rename GraphQL field `hasSolutions` to `hasReme... (#414895 - closed) we deprecated hasSolutions.

After 6 months, we can remove it.

Relevant links

Implementation plan

• Wait until %17.0
• Rebase draft MR: !137668 (merged)

Verification steps