json_view: no constant operand in the number dispatch (MSVC C4127)

The `!negative ||` that #6006 added to the digit test of the number scan has
a constant left operand in the template (negative is a template argument), so
MSVC reports C4127 under /WX in builder.hpp(1177). Restore the plain test; the
branch behaves the same.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/view/builder.hpp

@@ -1174,9 +1174,8 @@ indent_done:
             {
                 ++p;
             }
-            else if (!negative || NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
+            else if (NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
             {
-                // (without a sign, the dispatch saw a digit)
                 p = skip_digits(p + 1, e);
             }
             else