fix: do not allow GROUP BY and PARTITION BY on boolean expressions

[big-andy-coates]

Description

fixes: #4939

Change to SQL syntax to not allow GROUP BY and PARTITION BY on boolean expressions. Only value expressions will be allowed.

Testing done

usual

Reviewer checklist

• Ensure docs are updated if necessary. (eg. if a user visible feature is being added or changed).
• Ensure relevant issues are linked (description should include text like "Fixes #")

[blueedgenick]

oh this is an interesting one - i had to go do some digging to figure out what i expect to happen. Seems like the answer is that it's not the boolean expresson per se which is the problem, but "only" that we don't have a proper datatype for it's return value or a way to cast it to a 0/1 or "true"/"false" or other truthy value, right ? If we did then the output of the group by, for example, should have two groups: one for true and one for false.
Experiments suggest that mysql does some odd auto-casting thing and allows this to work (which i'm not a big fan of) whereas systems like postgres have a proper datatype they will automatically use, and so it works there too.
Perhaps, similar to Almog's suggestion on 4942, it might actually be better ux to leave the grammar as-is and throw a super-specific message from the analyzer instead until such time as we play nicer with bool types ?