Update Email-Text

[sabrina-ulbrich]

We get the feedback that it discourages some to sign up if it says they absolutely have to enter lectures.

Confirmation instruction says Please ensure that your profile includes information in both the My Bio and Examples of Previous Talks sections. This is crucial for activation of your profile.

I guess it's not the case that both have to be filled out and it's not necessary to link to talks but more generally references.

Maybe we should also rename the caption Biography into some wider meaning like "About me" or "work experience".