Metadata table: don't allow line breaks in certain columns

[lehkost]

In a play to be added to GerDraCor (not yet in the repo, only in the staging database for early testing) there's a line break in the <pubPlace> element of the source TEI file (which belongs to the <sourceDesc>):

• https://staging.dracor.org/ger/birch-pfeiffer-die-grille

This line break is also featured in the metadata table, like so:

Line breaks in this column should be deleted and usually replaced by a whitespace, like so: "Halle a. d. S."