refactor(ioscompanion): inline firstNonEmpty

internal/driver/ioscompanion/devicerunner.go

@@ -45,8 +45,12 @@ type signingCredentials struct {
 // readSigningCredentials gathers the signing inputs from the environment and
 // reports every missing one at once. The .p8 key must exist on disk.
 func readSigningCredentials() (signingCredentials, error) {
+	team := os.Getenv(envTeam)
+	if team == "" {
+		team = os.Getenv(envTeamFallback)
+	}
 	creds := signingCredentials{
-		team:         firstNonEmpty(os.Getenv(envTeam), os.Getenv(envTeamFallback)),
+		team:         team,
 		authKeyPath:  os.Getenv(envAuthKeyPath),
 		authKeyID:    os.Getenv(envAuthKeyID),
 		authIssuerID: os.Getenv(envAuthIssuer),
@@ -87,15 +91,6 @@ func VerifyDeviceSigning() error {
 	return err
 }
 
-func firstNonEmpty(values ...string) string {
-	for _, value := range values {
-		if value != "" {
-			return value
-		}
-	}
-	return ""
-}
-
 // realSpawnDeviceRunner regenerates the runner project, builds it for the device
 // (skipping when the cached build matches the current sources), injects the
 // session port into the device xctestrun, and spawns the test session that hosts