[NEXMANAGE-906] Truncate granular log instead of removing it

[yengliong93]

PULL DESCRIPTION

The dispatcher agent is unable to remove the granular log file in a read-only system. This PR modifies the dispatcher agent so that it truncates the file instead of removing it.

Impact Analysis

Info	Please fill out this column
Root Cause	Specifically for bugs, empty in case of no variants
Jira ticket	Add the name to the Jira ticket eg: "NEXMANAGE-622". Automation will do the linking to Jira

CODE MAINTAINABILITY

• Added required new tests relevant to the changes
• Updated Documentation as relevant to the changes
• PR change contains code related to security
• PR introduces changes that break compatibility with other modules/services (If YES, please provide description)
• Run go fmt or format-python.sh as applicable
• Update Changelog
• Integration tests are passing
• If Cloudadapter changes, check Azure connectivity manually

Code must act as a teacher for future developers

[yengliong93]

@gblewis1 please have a review, thanks.

[gblewis1]

Would like to run this through integration test, but Jenkins seems to be down. Will check later.

[gblewis1]

Jenkins still down due to Penang power outage. Approved, but need integration test first.

[yengliong93]

Integration tests pass.