fix: valid float parsing when pattern not include leading number before . ( .231 )

[eXponenta]

in some DWGs (and then DXFs after ODA transform ) MTEXT include width pattern as \W.85; instead of \W0.85;

(See the attached file.)

And this text will present then in text content.

Before:

After:

file:
mtext_invalid_char_width.dxf 2.zip

[eXponenta]

Now we got problem with test, because it think that .{d} is invalid instruction, when for cad it is ok.

{\fISOCPEUR|b0|i0|c0|p34;\Q.0;1\H.5x;2\H4.0x;\W.5;3\H.25x;\W1;4\H2.x;5}

is valid pattern.
see:
mtext_complex_test.dxf.zip