x11-toolkits/vte3: fix build with clang 16

Clang 16 has a new error about integer values being outside the valid
range for enum types, which shows up when building x11-toolkits/vte3:

../src/vtepty.cc:577:16: error: integer value 234881535 is outside the valid range of values [0, 4095] for this enumeration type [-Wenum-constexpr-conversion]
        return GSpawnFlags(G_SPAWN_LEAVE_DESCRIPTORS_OPEN |
               ^

Upstream already noticed this, and committed
https://gitlab.gnome.org/GNOME/vte/-/commit/9b41cd101429 as a fix, so
add this as an additional patch, until the next version is released.

PR: 271057
Approved by: maintainer timeout (2 weeks)
MFH: 2023Q2