Attribute order in layout xml is not consistent

[christophfroehlich]

Problem description

I observed that the order of the attributes is not consistent from one save to the next one (sometimes only if there were changes in the layout, sometimes without any changes). This results in an unnecessary big git diff.

For example
<plot flip_y="false" flip_x="false" mode="TimeSeries" style="Lines">
is the next time
<plot mode="TimeSeries" flip_x="false" style="Lines" flip_y="false">

This can be reproduced with

• any data (or -t option)
• create a layout
• save it
• reopen plotjuggler
• load layout
• save it
• load the diff from the two files

Answer these questions (or I will ignore your issue)

1. Describe your platform / Operative System and the version of PlotJuggler you are using.
   Ubuntu 22.04

Package: ros-humble-plotjuggler
Version: 3.9.1-1jammy.20240729.002837

3. Compile and try the latest version in the main branch and check if the problem persists.
   same result with 3.9.2 from main branch
4. Check if the problem can be reproduced using the dummy data created by the command line argument "-t" or one of the files in the folder "datasamples". not related to data
5. If it can't be reproduced with the dummy data, please share the CSV file or the rosbag that can be used to reproduce the problem. not related to data