remove region identifier prefix when making request to count tokens endpoint

[narengogi]

Description: (required)

• This removes region endpoint from url construction when making request to count tokens endpoint because it throws invalid model otherwise

Tests Run/Test cases added: (required)

• Tested the count tokens endpoint for both anthropic and non anthropic models for with and without region prefix
  example curl:

curl --location 'http://localhost:8787/v1/messages/count_tokens' \
--header 'x-portkey-provider: bedrock' \
--header 'Content-Type: application/json' \
--header 'x-portkey-aws-access-key-id: abc' \
--header 'x-portkey-aws-secret-access-key: abc' \
--header 'x-portkey-aws-region: us-west-2' \
--data-raw '{
    "model": "apac.anthropic.claude-sonnet-4-5-20250929-v1:0",
    "max_tokens": 10,
    "messages": [
      {
        "role": "user",
        "content": "hello there"
      }
    ]
    ]
  }'

Type of Change:

• Bug fix (non-breaking change which fixes an issue)