Support for bracket notation inside MULTIPOINT

[DaveGosselin-MariaDB]

MDEV-36166:  Accept bracketed points inside MULTIPOINT

ST_GEOMFROMTEXT('MULTIPOINT((0 0),(1 1))') returned NULL while
ST_GEOMFROMTEXT('MULTIPOINT(0 0,1 1)') returned the geometry.  The
bracketed spelling is the one the OGC WKT grammar defines.  In
06-103r4 section 7.2.2 a <multipoint text> is a list of <point text>,
and a <point text> has its own parentheses, the same way a
<multilinestring text> is a list of <linestring text>.  The bare
spelling matches no production in that grammar, so the text MariaDB
rejected was the conformant one.

The first point now determines which of the two bracketing forms the
remaining list elements will use.  A mixed list such as MULTIPOINT((0
0),1 1) is an error.  The bare form stays accepted because existing
data and applications use it.  Geometry::create_from_wkt is the single
entry into the WKT reader, so ST_MPOINTFROMTEXT and a MULTIPOINT
nested in a GEOMETRYCOLLECTION are covered by the same change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>