issue id #FM2-660resolve the issue PUT operation on Encounter resourc…

[Shubhamgoyalbs]

Reolved the issue having id #FM2-660 PUT operation on Encounter resource creates duplicate encounter providers

I have not access to assign this issue to me in website so I have directly made this request.

Description of what I changed

Resolved the issue where PUT operation on Encounter resource caused duplicate encounter providers to be created.
Modified the update logic to check for existing providers and prevent duplicates when updating an encounter.

Issue I worked on

see https://issues.openmrs.org/browse/FM2-660

[Shubhamgoyalbs]

Can any one help to test the changes

[ibacher]

When submitting a PR, please do not delete the checklist. Among other things, this asks to make sure that you ran mvn clean package before committing this. One of the things that does it to reformat your code so that there are fewer formatting issues in the PR.

Also, all PRs for this repo must have tests demonstrating that the issue here is fixed.

Please address these points before can properly review the PR.