Calc: How can I remove empty lines within a cell?

How can I remove empty lines within a cell? I tried to use this regular expression ^\s*$, but even though it matches empty lines on regex101 it doesn’t work in Calc.

P.S. I know it’s a bad practice to use multiline cells, but that’s the only option available to me)

In column B: =REGEX(A1;"\n \n";"";"g") to supress lines without text (there is a space in every line)

In column C: =REGEX(B1;": \R ";": ";"g") to join in a line Concept: and Value

Then copy column C, and paste as Text and Numbers.

Sample file.

LibreOffice Help on REGEX.

More info on Regular Expressions.

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