CI: test build fmuv3 bootloader in CI

fmuv3 and other 16k bootloaders were broken by a recent change

.github/workflows/test_chibios.yml

@@ -23,6 +23,7 @@ jobs:
             periph-build,
             iofirmware,
             CubeOrange-bootloader,
+            fmuv3-bootloader,
             revo-bootloader,
             stm32h7-debug,
             fmuv3,

Tools/scripts/build_ci.sh

@@ -245,6 +245,14 @@ for t in $CI_BUILD_TARGET; do
         continue
     fi
 
+    if [ "$t" == "fmuv3-bootloader" ]; then
+        echo "Building fmuv3 bootloader"
+        $waf configure --board fmuv3 --bootloader
+        $waf clean
+        $waf bootloader
+        continue
+    fi
+    
     if [ "$t" == "stm32f7" ]; then
         echo "Building mRoX21-777/"
         $waf configure --Werror --board mRoX21-777