Correct system width after right aligned segment

[miiizen]

Resolves: #19848
When a right aligned segment was placed immediately before an end barline, the measure width adjustment wasn't added to the system width.

• I signed the CLA
• The title of the PR describes the problem it addresses
• Each commit's message describes its purpose and effects, and references the issue it resolves
• If changes are extensive, there is a sequence of easily reviewable commits
• The code in the PR follows the coding rules
• There are no unnecessary changes
• The code compiles and runs on my machine, preferably after each commit individually
• I created a unit test or vtest to verify the changes I made (if applicable)