fix(build): prepare dependents for bootloader_support dropping mbedtls

bootloader_support is about to stop pulling mbedtls (and app_update) into
every build graph, so components and apps that relied on those transitive
edges must own their dependencies

Closes https://github.com/espressif/esp-idf/issues/18072
Related https://github.com/espressif/esp-idf/issues/18778

examples/build_system/cmake/import_prebuilt/main/CMakeLists.txt

@@ -1,4 +1,5 @@
 idf_component_register(SRCS "main.c"
+                    PRIV_REQUIRES app_update
                     INCLUDE_DIRS ".")
 
 # Import the library, specifying a target name and the library path.

examples/build_system/cmakev2/features/import_prebuilt/main/CMakeLists.txt

@@ -1,4 +1,5 @@
 idf_component_register(SRCS "main.c"
+                    PRIV_REQUIRES app_update
                     INCLUDE_DIRS ".")
 
 # Import the library, specifying a target name and the library path.