[UX] Fix GCP show-gpus order after combining VM types

[Michaelvll]

The current price order for GCP in sky show-gpus is incorrect, because:

1. The VM price used for the total price is the cheapest one across all regions instead of the current region.
2. We only sort the price before combining the price of VM and GPUs. This PR re-sort the price/spot price after combining GPU and host VM price.

It also fixes #2953.

Tested (run the relevant ones):

• Code formatting: bash format.sh
• Any manual or new tests for this PR (please specify below)
  • sky show-gpus a100
  • sky show-gpus a100 --all-regions
  • sky show-gpus
  • sky show-gpus v100:1 --all-regions
    Before this PR

  sky show-gpus v100:1 --cloud gcp --all-regions
  GPU   QTY  CLOUD  INSTANCE_TYPE  DEVICE_MEM  vCPUs  HOST_MEM  HOURLY_PRICE  HOURLY_SPOT_PRICE  REGION        
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 0.811            asia-east1    
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.013            us-central1   
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.013            us-east1      
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.013            us-west1      
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 3.023       $ 0.938            europe-west4  
  

  After this PR
  ```console
  $ sky show-gpus v100 --cloud gcp --all-regions
  GPU   QTY  CLOUD  INSTANCE_TYPE  DEVICE_MEM  vCPUs  HOST_MEM  HOURLY_PRICE  HOURLY_SPOT_PRICE  REGION        
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.037            us-central1   
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.037            us-east1      
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 2.953       $ 1.037            us-west1      
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 3.028       $ 0.845            asia-east1    
  V100  1    GCP    n1-highmem-8   -           8      52GB      $ 3.071       $ 0.973            europe-west4  

Note: for example, asia-east1 has different hourly price, because before this PR we use the same VM price for all different regions which is not correct.

• All smoke tests: pytest tests/test_smoke.py
• Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• Backward compatibility tests: bash tests/backward_comaptibility_tests.sh

[cblmemo]

Seems like we are keeping the first entry in the list. Why is that the cheapest?

[Michaelvll]

Because we have sorted it by the price in L454. : )

[cblmemo]

Thanks! LGTM. Left a nit on readability

[concretevitamin]

This seems to slow down show-gpus significantly. Any quick way to fix?

» time sky show-gpus --cloud gcp

• This PR: 6.19s user 0.47s system 98% cpu 6.771 total
• 872d969: 1.22s user 0.43s system 114% cpu 1.437 total