DRTVWR-575: Replace some LLSDArray() usage with llsd::array().

It seems newer compilers have a different interpretation of exactly when to
engage LLSDArray's copy constructor. In particular, this assignment:

some_LLSD_map[key] = LLSDArray(...)(...)...;

used to convert the LLSDArray object directly to LLSD; now it first calls the
custom copy constructor, which embeds the intended array within an outer array
before assigning it into the containing map.

The newer llsd::array() function avoids that problem because what it returns
is already an LLSD object.

Taking inventory of LLSDArray assignments of that form turned up a number of
workarounds like LLSD(LLSDArray(...)). Replacing those with llsd::array() is
both simpler and more readable.

Tip of the hat to Chorazinallen for surfacing this issue!