new snapshot for stack build

[vidit-od]

Fixes #4696

This PR does :

• remove ghc 9.6 stack build option
• introduces ghc 9.10 stack build
• fixes a few of the redundant imports that caused build problems.

this now enables us with 2 stack builds

• Ghc 9.8 ( stack.yaml )
• Ghc 9.10 ( stack-lts24.yaml )

[vidit-od]

Edit : I re-ran circleci failure and it passed this time.
Any reason for this flakyness ?

Original :
Regarding Stackage-lts23 failure.
Need some direction here on how to update the Stack version.

This is wrt ghc 9.8 version ( corresponding to stack.yaml )
The CircleCi logs say :

Warning: You are currently using Stack
         version 3.3.1 but version 3.9.3
         is available.
         
         You can try to upgrade by running
         stack upgrade
         
         Tired of seeing this? Add
         recommend-stack-upgrade: false
         to /root/.stack/config.yaml.

[fendor]

@vidit-od I think we shouldn't bother too much with circle ci, let's get this merged and then migrate the circle ci jobs to github. We just need to be careful not overstretch our cache size.

[vidit-od]

Edit :
ok i was wrong here, Flag tests do do a one more thing that makes them important. They test normal build & build with non default flags for all the ghc variants. There is no way to test the latter part using testing github actions.

below suggestion can be ignored :)

original :
@fendor makes sense;
i am not sure if this will help but we can also investigate about Flag tests on github maybe ?
although, i am not sure if it will have a significant ( or any ) form of cache relaxation

from what i understand, those tests are just for build checks only. we can delegate this to our Testing tests on github. The only extra thing these tests provide is : if any one fails all of the other flag tests gets cancelled.

thank you for reviewing the PR ;

[fendor]

Some comments as well :)

[vidit-od]

@fendor , i tried to eliminate the conditional imports but i could not find any clean way to do that.
is there any way to ignore redundant import errors maybe ?

[fendor]

Thanks, one CPP we can avoid, the others also already contain CPP, so it is fine.

[fendor]

LGTM, thank you!