fbt: added -Wstrict-prototypes for main firmware (#3557)

* fbt: added -Wstrict-prototypes for main firmware (excludes extapps)
* unit_tests: fixed declarations using strict prototypes
* furi_hal: ble: changed gap stop log level to debug

Co-authored-by: あく <alleteam@gmail.com>

site_scons/cc.scons

@@ -4,6 +4,7 @@ Import("ENV")
 ENV.AppendUnique(
     CFLAGS=[
         "-std=gnu2x",
+        "-Wstrict-prototypes",
     ],
     CXXFLAGS=[
         "-std=c++20",

site_scons/extapps.scons

@@ -48,6 +48,9 @@ appenv.AppendUnique(
         "stdc++",
         "supc++",
     ],
+    CFLAGS=[
+        "-Wno-strict-prototypes",
+    ],
 )