Add a separate PF accurate previews feature flag

[VenelinMartinov]

We've decided to postpone rolling out PF accurate previews, so the SDKv2 bridge and the PF bridge need separate feature flags. This change adds a new feature flag for PF and keeps the old one for the SDKv2.

related to #2598

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 68.63%. Comparing base (d9d48ae) to head (f626162).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/pf/tfbridge/provider.go	0.00%	3 Missing and 1 partial ⚠️
pkg/pf/tfbridge/provider_diff.go	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2808      +/-   ##
==========================================
- Coverage   68.73%   68.63%   -0.11%     
==========================================
  Files         325      325              
  Lines       41536    41536              
==========================================
- Hits        28549    28507      -42     
- Misses      11381    11423      +42     
  Partials     1606     1606              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[guineveresaenger]

Three thoughts:

1. Should we add a separate env var for this as well?

2. It's a little unfortunate that EnableAccurateBridgePreview doesn't really convey that it's SDKv2 only, I appreciate the callout on info.go

3. do we intend to keep any of these feature flags longterm? Is the goal to eventually onboard every provider and then remove these flags? Or will we consolidate them? Leave both?

[VenelinMartinov]

1. Yup, good point, I've added one in case we have a use for that.
2. It is unfortunate but I've opted to keep the public interface backwards compatible instead. I think the slight misnaming should be fine here.
3. Yup, that's the plan. Onboard all providers and then deprecate the flags. PF is on hold for now.

[guineveresaenger]

thank you for adding the env var!

I agree that a breaking change would be entirely too much work here for not enough gain. 👍