unit_test_app: remove libsodium config for esp32s2

This configuration overflows DRAM size for esp32s2 and hence
resulting in CI failure. Removing this config as it does not
add any value in esp32s2 context.

tools/unit-test-app/configs/libsodium_s2

@@ -1,4 +0,0 @@
-TEST_COMPONENTS=libsodium
-TEST_EXCLUDE_COMPONENTS=bt app_update
-CONFIG_UNITY_FREERTOS_STACK_SIZE=12288
-CONFIG_IDF_TARGET="esp32s2"