[Bug] Paddy overrides settings to pin element to top of container
### Bug report
#### Expected behavior:
Expect that Paddy will not unnecessarily modify element (resizing) alignment


#### Actual behavior:
Paddy modifies the alignment of nested text when it runs. This instance of it seems to be related to updating a symbol item, (maybe) only when there are symbol instances that are also getting updated?

recording: https://www.dropbox.com/s/sa4r0f9pjuzh0ik/paddy-bug-alignment.mov?dl=0

#### Steps to reproduce:
Create a symbol with text and set the alignment to be vertically centered (not pinned to top or bottom).  Create an instance of the symbol and update the original symbol so Paddy runs and alters it. As I experience it, the text element keeps getting pinned to the top of the element. The issue seems to only appear when there are instances of that symbol that are also getting updated.

sketch file: https://www.dropbox.com/s/30rydl39xu6e2wa/paddy-test.sketch?dl=0

