Text Alignment button shows left aligned for a full selection (can't make text left aligned again)
#### Summary:
When changing the text alignment of some text to anything but left-aligned, the button goes back to show left-aligned (even though the text is not correctly aligned).
As a consequence (or maybe independent issue?), it is not possible to use that button to go back to left-alignment.
#### Steps to reproduce:
<!-- Describe what you did (step-by-step) so we can reproduce: -->
- Open Inkscape
- Create a text object and type in a few letters (ex: "abcdef"), then next line, then another few letters (more or less than the previous line − ex: "abc")
- Highlight the whole text
- Click the "text alignment button" and select "centered" or "right-aligned"
- Make sure the text is still highlighted
- Click the "text alignment button" and try to select "left-aligned"
#### What happened?
After the text was centered or right-aligned, the button went back to show "left-aligned", incorrectly reporting the state of the text.
The text cannot be left-aligned anymore once it has been centered or right-aligned.
#### What should have happened?
- The button should reflect properly the state of the text.
- It should be possible to left-align the text again.
Sample attachments:

#### Version Info:
```
- Inkscape Version: 1.0 (4035a4f, 2020-05-01)
- Operating System: macOS
- Operating System version: Catalina (10.15.5)
```
<!--
Please be careful when/after writing # for example in logs, code, or versions of linux
- use inline code span - single backticks (`) before and after it, like this - `inbox#1618`
- use multi-line code block - triple backticks (```) to fence/enclose console logs
- attach long logs as a text file.
-->
issue