Accordion default icon changes shapes if title text is on multiple rows

[stefan-cotitosu]

Description

When using the accordion block, if the tab title expands on multiple rows, the shape of the icon is changed. I used the block in a sidebar in the following screenshot.

Step-by-step reproduction instructions

1. Add the accordion block (in a sidebar will be easier to test)
2. Use at least three tabs
3. Set a longer title for one of the tabs to expand on multiple rows
4. Test the icon shape on the front end

Screenshots, screen recording, code snippet or Help Scout ticket

Reported here: https://secure.helpscout.net/conversation/2398399167/390166/

Environment info

https://pastebin.com/u0a1cFFw

Is the issue you are reporting a regression

No

[girishpanchal30]

@stefan-cotitosu I have fixed it with this PR #2770