"Convert to text" results in wrong alignment for SVG1.2 flowed text

Migrated from: https://bugs.launchpad.net/inkscape/+bug/497469

Steps to reproduce:

• open Inkscape
• Make sure that SVG2 text is deactivated
• Drag with text tool to create flowed text.
• Type several lines of flowed text. Lines should be of different lengths so that alignment is visible.
• Align to center or right.
• Select Text -> Convert to text

What happened?

• Alignment of the resulting text is wrong.
• Selecting "Align left" from text toolbar fixes the problem.

What should have happened?

The alignment of the text stays correct.

Selecting Align left replaces text-anchor:middle with text-anchor:start.

For SVG2 text, the function doesn't do anything ("No flowed texts in selection"). Bad wording of the status message?

Inkscape Version and Operating System:

• Inkscape Version: 1.1-dev (12e2a09, 2020-02-19)
• Operating System: Windows 10
• Operating System version: 10.0.18362

Migration info:

• Inkscape 0.47pre4
• Inkscape 0.47 r22583 on OS X 10.5.8
• Inkscape 0.48+devel r9823 on OS X 10.5.8
• Inkscape 0.48+devel r11575
• Inkscape 0.91pre2 r
• Inkscape 0.92.1 (and 0.91)

Workaround:

sed 's/text-align:center;text-anchor:middle/text-align:start;text-anchor:start/' -i "$TMP"
sed 's/text-align:end;text-anchor:end/text-align:start;text-anchor:start/' -i "$TMP"