DG-1950 Added field of keyword for task_guid

[hr2904]

Change description

Currently __task_guid have text type ES index mapping which does not allow targetted fetching of tasks based on these filter, rather allows match based which returns correct response along with multiple near matching docs.

Type of change

• New feature (adds functionality)

Related issues

Fix #1

Checklists

Development

• Lint rules pass locally
• Application changes have been tested thoroughly
• Automated tests covering modified code pass

Security

• Security impact of change has been considered
• Code follows company security practices and guidelines

Code review

• Pull request has a descriptive title and context useful to a reviewer. Screenshots or screencasts are attached as necessary
• "Ready for review" label attached and reviewers assigned
• Changes have been reviewed by at least one other contributor
• Pull request linked to task tracker where applicable