Add input validation for `NumberDeserializers` deserializers for "stringified" FP numbers

[cowtowncoder]

Describe your Issue

Although all decoding/parsing of true JSON numbers validates that tokens follow expected pattern, before calling number methods, deserializers in NumberDeserializers do not seem to do that for "stringified Numbers" (that is, JSON Strings that contain Numbers). But Floating Point decoders expect such validation to be done before calling methods via jackson-core package's NumberInput methods.

So let's add validation for alleged FP numbers.

[cowtowncoder]

(note: PRs that fixed this did not refer the issue, unfortunately)