CLI: Fix framework migration handling

[shilman]

Is your feature request related to a problem? Please describe

Currently getStorybookInfo incorrectly returns a renderer as a framework, which is wrong and may cause bugs in various uses

Describe the solution you'd like

• Remove framework/frameworkPackage from getStorybookInfo
• Get rid of the 6.5 frameworks migration
• Update the 7.0 new-frameworks migration to:
  • Deal with an empty framework field since the old migration won't run
  • Deal with an old framework field as it already does
  • Run early in the automigrations list so that later automigrations have access to framework
• Use csf-tools/ConfigFile to get framework from main.js everywhere

Describe alternatives you've considered

No response

Are you able to assist to bring the feature to reality?

no

Additional context

No response

[shilman]

closing as dupe to #20955