[@Powerpages Copilot] Context Improvement for Webpage

[amitjoshi438]

This pull request introduces several enhancements to the PowerPagesChatParticipant class and related utilities, focusing on managing and fetching related files for a given context. The most important changes include adding support for fetching related files based on the active file's context, updating schemas for file extensions, and modifying API requests to include related files.

Enhancements to file management:

• src/common/utilities/Utils.ts: Added functions getFileContent, getFileContentByType, and fetchRelatedFiles to manage and fetch related files based on the active file's context.

Schema updates:

• src/common/constants.ts: Defined componentTypeSchema and relatedFilesSchema to map file types and their extensions, and added an interface IRelatedFiles for related files.

API request modifications:

• src/common/copilot/IntelligenceApiService.ts: Updated sendApiRequest to include an optional RelatedFiles parameter and modified the request payload to include related files. [1] [2]

Class updates:

• src/common/chat-participants/powerpages/PowerPagesChatParticipant.ts: Integrated the fetchRelatedFiles function to fetch and include related files in the API request within the PowerPagesChatParticipant class. [1] [2]

Minor updates:

• src/common/copilot/constants.ts: Added css to the FieldTypeMap.
• Removed an extraneous line in src/common/chat-participants/powerpages/PowerPagesChatParticipantUtils.ts.