feat(subscription): Add support to estimate for a subscription in chargebee (#9336)

Co-authored-by: Spriti Aneja <spriti.aneja@juspay.in>
Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>
Co-authored-by: spritianeja03 <146620839+spritianeja03@users.noreply.github.com>
Files to modify:


**chargebee.rs**
  Add:
    - function: private::get_headers
    - function: private::get_url
    - function: private::get_content_type
    - function: private::get_request_body
    - function: private::build_request
    - function: private::handle_response
    - function: private::get_error_response
    - impl: impl api::subscriptions::GetSubscriptionEstimateFlow for Chargebee
    - impl: impl ConnectorIntegration<
GetSubscriptionEstimate,
GetSubscriptionEstimateRequest,
GetSubscriptionEstimateResponse,
> for Chargebee

**transformers.rs**
  Add:
    - function: private::try_from
    - function: private::try_from
    - struct: pub::ChargebeeSubscriptionEstimateRequest
    - struct: pub::SubscriptionEstimateResponse
    - struct: pub::ChargebeeEstimate
    - struct: pub::SubscriptionEstimate
    - struct: pub::InvoiceEstimate
    - struct: pub::LineItem
    - impl: impl TryFrom<ResponseRouterData<F, SubscriptionEstimateResponse, T, GetSubscriptionEstimateResponse>> for RouterData<F, T, GetSubscriptionEstimateResponse>
    - impl: impl TryFrom<&GetSubscriptionEstimateRouterData> for ChargebeeSubscriptionEstimateRequest

**recurly.rs**
  Add:
    - impl: impl api::subscriptions_v2::GetSubscriptionEstimateV2 for Recurly
    - impl: impl ConnectorIntegrationV2<
GetSubscriptionEstimate,
GetSubscriptionEstimateData,
GetSubscriptionEstimateRequest,
GetSubscriptionEstimateResponse,
> for Recurly

**default_implementations.rs**
  Add:
    - impl: impl GetSubscriptionEstimateFlow for $connector
    - impl: impl ConnectorIntegration<
GetSubscriptionEstimate,
GetSubscriptionEstimateRequest,
GetSubscriptionEstimateResponse
> for $connector
    - impl: impl GetSubscriptionEstimateFlow for connectors::DummyConnector<T>
    - impl: impl ConnectorIntegration<
GetSubscriptionEstimate,
GetSubscriptionEstimateRequest,
GetSubscriptionEstimateResponse,
> for connectors::DummyConnector<T>

**flow_common_types.rs**
  Add:
    - struct: pub::GetSubscriptionEstimateData

**subscriptions.rs**
  Add:
    - struct: pub::GetSubscriptionEstimate

**subscriptions.rs**
  Add:
    - struct: pub::GetSubscriptionEstimate

**subscriptions.rs**
  Add:
    - struct: pub::GetSubscriptionEstimate

**types.rs**
  Modify existing code

**subscriptions.rs**
  Add:
    - struct: pub::GetSubscriptionEstimate

**subscriptions_v2.rs**
  Add:
    - trait: private::GetSubscriptionEstimateV2

**types.rs**
  Modify existing code

**api.rs**
  Modify existing code