Use notification main link if no parameter has a link

[julien-nc]

Maybe I didn't get it but if main notification link and rich parameter links are mutually exclusive (to avoid nested links I guess), there is a mistake here 😁.

If I indeed didn't get it, I can still testify: the main link is not used with a basic notification definition like:

$notification->setParsedSubject($subject)
    ->setLink($link)
    ->setIcon('blabla');

[ChristophWurst]

👍 🐘

[nickvergessen]

Look right, but didn't test

[nickvergessen]

And yeah they should be mutual exclusive to avoid nesting.

[nickvergessen]

/backport to stable21

[nickvergessen]

/backport to stable20