Some characters: `'`, `"`, and `\`, can cause problems with RNA paths.
Instead of using more complicated handling to deal with those cases,
we can just prevent these characters from being used in custom property
names.
This commit checks for these characters to `idp_try_read_name`, where
other checks like length are already done.
Differential Revision: https://developer.blender.org/D8839
cbae82ba96