[Rust][reqwest] Fixed parameters of Array type

Created by: JRAndreassen

@frol / @farcaller / @richardwhiuk / @paladinzh

Fixed parameters of Array type in "rust/reqwest/api.mustache"

the following definition:

        - description: Secret Mode. Mandatory for 'Node-Locked' licensing model.
          in: formData
          items:
            default: PREDEFINED
            enum:
              - PREDEFINED
              - CLIENT
            type: string
          name: nodeSecretMode
          required: false
          type: array

Fix for api_mustache ignoring Array's in parameters... error[E0599]: no method named join found for reference &str in the current scope --> src\apis\product_module_api.rs:110:62 | 110 | form_params.insert("nodeSecretMode", param_value.join(",").to_string()); | ^^^^ method not found in &str Not using #isListContainer in parameters

Fixed for both standard and "vendorExtensions.x-group-parameters=true" and compiles under both