Fixes several UI Issues identified in the Design Assistant

[Arshardh]

Purpose

This PR includes several changes to the UI of API Design Assistant.
Related issue: wso2/api-manager#3564

1. Removes the API type from the sample query cards, rearranges the order and placing and adds a new card for GraphQL APIs.
   

2. Aligns the loading dots with the 'Generating a response' text and also shifts this component a little bit to the right.
   

3. Adds a download button for all API types next to the 'View Source' toggle (for REST APIs) to enable downloading the source code of the API specification.

Below is an image of how it is shown for REST APIs.

Below is an image of how it is shown for GraphQL or Async APIs.

Below is an image of it having the functionality to download the spec to their 'Downloads' folder.

4. Adds functionality to respond to simple non-API related questions and statements.
   

Below is an image of the assistant creating an API after asking non-API related questions.

Related issue: wso2/api-manager#3564

This PR also includes

1. Allowing .graphql files to be downloaded from the Download button.
   The purpose of this is to enable .graphql files for GraphQL APIs and .yaml files for REST and Async APIs to be downloaded as a .yaml file for GraphQL APIs is not suitable.

2. Adding a confirmation pop up for 'Create API' in API Design Assistant.
   The purpose of this is to ensure the user confirms that they are ready to create the API and want to move to the API Creation Wizard.
   

[sonarqubecloud]

Quality Gate failed

Failed conditions
41.8% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud