Bug 1885794 - Fix opening external attachments when is required. r=rjl

Differential Revision: https://phabricator.services.mozilla.com/D207142

--HG--
extra : amend_source : 739da6371ee968532f3ba62aaa78bfae28bd5e8c

taskcluster/docker/tb-flatpak/repack.sh

@@ -156,28 +156,29 @@ install -D -m755 launch_script.sh "${appdir}/bin/thunderbird"
 # (org.mozilla.Thunderbird) does not match bus names
 # (org.mozilla.thunderbird, lowercase "t"). The app ID may be updated
 # in the future to match the default bus names.
-flatpak build-finish build                                      \
-        --allow=devel                                           \
-        --share=ipc                                             \
-        --share=network                                         \
-        --socket=pulseaudio                                     \
-        --socket=wayland                                        \
-        --socket=x11                                            \
-        --socket=pcsc                                           \
-        --socket=cups                                           \
-        --require-version=0.10.3                                \
-        --persist=.thunderbird                                  \
-        --filesystem=xdg-download:rw                            \
-        --filesystem=~/.gnupg                                   \
-        --filesystem=xdg-run/gnupg:ro                           \
-        --filesystem=xdg-run/speech-dispatcher:ro               \
-        --filesystem=/run/.heim_org.h5l.kcm-socket              \
-        --device=all                                            \
-        --own-name="org.mozilla.thunderbird.*"                  \
-        --own-name="org.mozilla.thunderbird_beta.*"             \
-        --talk-name="org.gtk.vfs.*"                             \
-        --talk-name=org.a11y.Bus                                \
-        --system-talk-name=org.freedesktop.NetworkManager       \
+flatpak build-finish build                                        \
+        --allow=devel                                             \
+        --share=ipc                                               \
+        --share=network                                           \
+        --socket=pulseaudio                                       \
+        --socket=wayland                                          \
+        --socket=x11                                              \
+        --socket=pcsc                                             \
+        --socket=cups                                             \
+        --require-version=0.10.3                                  \
+        --persist=.thunderbird                                    \
+        --filesystem=xdg-download:rw                              \
+        --filesystem=~/.gnupg                                     \
+        --filesystem=xdg-run/gnupg:ro                             \
+        --filesystem=xdg-run/speech-dispatcher:ro                 \
+        --filesystem=/run/.heim_org.h5l.kcm-socket                \
+        --device=all                                              \
+        --own-name="org.mozilla.thunderbird.*"                    \
+        --own-name="org.mozilla.thunderbird_beta.*"               \
+        --talk-name="org.gtk.vfs.*"                               \
+        --talk-name=org.a11y.Bus                                  \
+        --system-talk-name=org.freedesktop.NetworkManager         \
+        --env=TMPDIR=~/.var/app/org.mozilla.Thunderbird/cache/tmp \
         --command=thunderbird
 
 # Export Flatpak build into repo