scm: file change tree should highlight active editor

[vince-fugnitto]

Bug Description:

If a given file is present in the scm-view it's corresponding file-tree node should be selected/highlighted. Currently, when setting focus to the file the tree is not updated:

scm-selection.mp4

Steps to Reproduce:

1. start the application with a workspace under git version control
2. perform changes in two files
3. open the scm-view and open the working tree changes for both
4. switching between the two files does not reflect in the tree selection