Fix Software Update URL and Release Date fields should not be required

[nmgaston]

PULL DESCRIPTION

Changes the URL and Release Date to optional for Software Update in the common.proto file.
Utilizes the validate.proto file that is also used in UDM.

Impact Analysis

Info	Please fill out this column
Root Cause	URL and ReleaseDate were set to required for Software Update when they should be optional
Jira ticket	NEXMANAGE-1280

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