fix for NPE in JDBCTypeMetaData

[alex0x08]

Hi, got this NPE after H2 upgrade to 2.2.222 (latest) version:

This was taken from "H2 Console" subproject, which I use in combination with your driver. So I observed driver sources and found a place that looks like very simple bug. For sure, there must be more complicated reason for such NPE, but function 'getMaxPrecision()' below has the same check as in PR: type = type.unwrap(); PGType pgType = PGType.valueOf(type); if (pgType == null) { return 0; } So hope this is just small and annoying bug, nothing more. After patch: