become flags are primary

with new configuration the sudo flags are always set and become cannot override,
switching to simle 'or' will result in become_flags working.

also sudo_flags are deprecated.
also changed from YAML null causing a 'None' str

fixes #30629

lib/ansible/config/base.yml

@@ -400,7 +400,7 @@ DEFAULT_BECOME_EXE:
   - {key: become_exe, section: privilege_escalation}
 DEFAULT_BECOME_FLAGS:
   name: Set 'become' executable options
-  default: ~
+  default: ''
   description: Flags to pass to the privilege escalation executable.
   env: [{name: ANSIBLE_BECOME_FLAGS}]
   ini:
@@ -1001,7 +1001,7 @@ DEFAULT_SU_EXE:
   - {key: su_exe, section: defaults}
 DEFAULT_SU_FLAGS:
   name: su flags
-  default: ~
+  default: ''
   deprecated:
     why: In favor of become which is a generic framework
     version: "2.8"