fix: exit with returncode 0 if no jwt token is obtained over dbus

`mender-inventory-mender-configure` produces an error when failing to
fetch the JWT token over DBus. If we exit with 1 mender-update will log:
```
raspberrypi mender-update[1070]: An authentication token could not be obtained over DBus.
mender-update[1029]: record_id=3 severity=error time="2025-Jun-12 21:53:25.802076" name="Global" msg="'/usr/share/mender/inventory/mender-inventory-mender-configure' failed: Process...
```
Now it will log:
`raspberrypi mender-update[1070]: mender-inventory-mender-configure: An authentication token could not be obtained over DBus.`

Changelog: Exit with returncode 0 in `mender-inventory-mender-configure`
if no jwt token is obtained over dbus. This stops mender-update from logging
errors from the inventory script before mender-auth is ready or if the
device isn't accepted.

Ticket: MEN-8591

Signed-off-by: Daniel Skinstad Drabitzius <daniel.drabitzius@northern.tech>

Author: danielskinstad

src/mender-inventory-mender-configure

@@ -44,7 +44,9 @@ SERVER="$(echo "$DBUS_REPLY" | sed -ne '2p')"
 
 if [ -z "$AUTH_TOKEN" ]; then
     echo "mender-inventory-mender-configure: An authentication token could not be obtained over DBus."
-    exit 1
+    # Don't produce an error. Most likely mender-auth is not ready or
+    # the device hasn't been accepted
+    exit 0
 fi
 if [ -z "$SERVER" ]; then
     echo "mender-inventory-mender-configure: A server address could not be obtained over DBus."

tests/unit/test_inventory.sh

@@ -76,7 +76,7 @@ testInvalidEndpoint() {
 testMissingJwtToken() {
     export TEST_AUTH_TOKEN_EMPTY=1
     output="$("${inv_script}")"
-    assertNotEquals 0 $?
+    assertEquals 0 $?
     assertEquals "" "${output}"
     assertEquals "" "$(cat "$TEST_HTTP_LOG" 2>/dev/null)"
 }