Always take ownership from UIThreadContext when rename commit

[Cosifne]

In the current build, if the rename commit takes long time, when the commit is not triggered by 'enter'.
Your won't be able to cancel the operation.

Before:

After:

It happens when I type 'ctrl + s' to commit the rename.

Fix is always taking ownership from the UIContext when commit starts.
We already do this in enter command handler,

roslyn/src/EditorFeatures/Core/InlineRename/CommandHandlers/AbstractRenameCommandHandler_ReturnHandler.cs

Line 22 in f915125

context.OperationContext.TakeOwnership();

Later rename session would choose to use IUIThreadOperationContext or IBackgroundIndicator by itself.