fix: integrate plausibility log messages

There were problems with formatting when integrating gt-gen-core into ASTAS because in some tests the {} brackets were replaced with the regex string .+ instead of a floating point number which caused an exception in formatting. This solution works with both floating point and the .+ string. The previous solution ":.3" didn't work because for floating-point types the default formatting is "g", which then doesn't give the right precision after the dot for numbers >=1. Therefore, reverted formatting to way it was before.