[EditOppComponent] Implement Unit tests

[EhsanEhrari]

• [x] should initialize Salesforce stage form with correct values for Candidate Opportunity
• [x] should dismiss modal on cancel
• [x] should close modal with opportunity progress params on save
• [x] should update parent job and close modal on save when copyToParentJob is true
• [x] should handle error in checkOpenCases
• [x] should set isOnlyOpenCaseOfParentJob to true if there is only one open case of parent job
• [x] should set isOnlyOpenCaseOfParentJob to false if there are multiple open cases of parent job
• [x] should set isOnlyOpenCaseOfParentJob to false if the opportunity is closed
• [x] should update stageHelpRequest on stage selection change for Candidate Opportunity