fix: sfn update to use template file for applying stack

[yongjun-chee]

Fixes #310
When updating stack introduces a new parameter, although it's in output of --apply-stack, current sfn update prompts user input for the parameter. It's because populate_parameters function checks for the current stack's template, not the given template file.

(I've added additional loggings for debugging purposes)
Without this fix, it's prompting user input for SsmStopRoleArn2 because receiver_stack (sfn-stack-2) valid_parameters didn't check the newly given template's parameters.

$ sfn update --defaults --yes sfn-stack-2 --apply-stack sfn-stack-1 --file ./template2.json
[Sfn]: SparkleFormation: update
[Sfn]:   -> Name: sfn-stack-2 Path: ./template2.json
[Sfn]: apply_stacks - remote_stacks ["sfn-stack-1"]
[Sfn]: execute_apply_stack 
receiver_stack (sfn-stack-2) valid_parameters: ["SsmStopRoleArn1"]
providing_stack (sfn-stack-1) outputs: SsmStopRoleArn2 arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test2
providing_stack (sfn-stack-1) outputs: SsmStopRoleArn1 arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test
[Sfn]: after apply - stack.parameters {}
[Sfn]: Stack runtime parameters:
[Sfn]: Ssm Stop Role Arn2: 

With this fix, receiver_stack (sfn-stack-2) valid_parameters detects the newly introduced parameter, and it applies the value from the outputs.

$ sfn update --defaults --yes sfn-stack-2 --apply-stack sfn-stack-1 --file ./template2.json
[Sfn]: SparkleFormation: update
[Sfn]:   -> Name: sfn-stack-2 Path: ./template2.json
[Sfn]: apply_stacks - remote_stacks ["sfn-stack-1"]
[Sfn]: execute_apply_stack 
receiver_stack (sfn-stack-2) valid_parameters: ["SsmStopRoleArn1", "SsmStopRoleArn2"]
providing_stack (sfn-stack-1) outputs: SsmStopRoleArn2 arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test2
providing_stack (sfn-stack-1) outputs: SsmStopRoleArn1 arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test
[Sfn]: after apply - stack_update.parameters {"SsmStopRoleArn2"=>"arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test2", "SsmStopRoleArn1"=>"arn:aws:iam::123412341234:role/SSM_Stop_RDS_rds-test"}
[Sfn]: Stack runtime parameters:
[Sfn]: Pre-update resource planning report:

  Update plan for: sfn-stack-2
    No resource lifecycle changes detected!

[Sfn]: Events for Stack: sfn-stack-2
Time                        Resource Logical Id   Resource Status      Resource Status Reason   
2023-10-20 12:11:49 -0400   sfn-stack-2           UPDATE_IN_PROGRESS   User Initiated           
2023-10-20 12:11:53 -0400   KeepRDSStopped1       UPDATE_IN_PROGRESS                                             
2023-10-20 12:11:54 -0400   KeepRDSStopped1       UPDATE_COMPLETE                                                
2023-10-20 12:11:57 -0400   sfn-stack-2           UPDATE_COMPLETE_CLEANUP_IN_PROGRESS                            
2023-10-20 12:11:58 -0400   sfn-stack-2           UPDATE_COMPLETE                                                
[Sfn]: Stack update complete: SUCCESS