Resolve "Scope and Service value are overwrited in update form"

What does this MR do and why?

Correct the selected value form dropdown field Scope/Service in Monitor/Incident/Maintenance update forms

MR acceptance checklist

• My code follows the style guidelines of this project
• I ran pylint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• My code needed automated testing. I have added them (this is optional task)
• I have added user readable comment in the CHANGELOG

Closes #60 (closed)