T&A #41600: Change byline of Test Setting "Introductory message"

[dsstrassner]

for ilias_de & ilias_en.lang. Please cherry pick also to Trunk.

[dsstrassner]

The feature request states as the second part of the Byline: "The message can be edited in the sub-tab "Introductory Message" of these settings and is accessible already before the test can be started." - The sub-tab part is missing, but the JourFixe decision has no information whether this byline part is okay or not. So, I changed only the "info" to "test"-tab. Maybe @matthiaskunkel could state, if we should add the "sub-tab" info also ;-)

[matthiaskunkel]

And adding an additional information about where the introductory message is created would be fine for me.

[dsstrassner]

Done ;-)

[thojou]

Hey @dsstrassner,

i took your PR and integrated the changes into trunk.

Thank you.