Updating Property Managers of a Property does not work

[Chris-Boe]

Describe the bug
A clear and concise description of what the bug is.
Attempting to edit a Property and add a property manager does not apply the change correctly. There are two issues here:

• UI submits the request to update the property and takes the UI out of Edit mode as soon as you click a property manager from the dropdown when it should only update the property when the save button is clicked
• Backend does not use the propertyManagerIDs request parameter to update the Property's assigned Property Managers

To Reproduce
Steps to reproduce the behavior:

1. Go to Properties list
2. Click on a property to edit it
3. Click edit using the pencil icon
4. Select a property manager from the search bar dropdown (population of the dropdown fixed by #801 )
5. See that the property manager was not correctly assigned

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.