Remove redundant SSH public file checks in callers of core/keys.py's generate_ssh_keys

[adewaleo]

In #7105, code to check if an SSH public key file exists were added to generate_ssh_keys in src/azure-cli-core/azure/cli/core/keys.py. However, the callers of this function essentially make this check. So we should update them and remove these checks.

See:

• _generate_ssh_keys() in src/command_modules/azure-cli-batchai/azure/cli/command_modules/batchai/custom.py

• validate_ssh_key() in src/command_modules/azure-cli-acs/azure/cli/command_modules/acs/_validators.py

• validate_ssh_key() in src/command_modules/azure-cli-vm/azure/cli/command_modules/vm/_validators.py

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Environment summary

N/A

[yugangw-msft]

Remove service flags which would cause the issue gets surfaced to s360