Update bats tests with new password paradigm

internal/tests/cli/boundary/_accounts.bash

@@ -1,5 +1,6 @@
 function create_account() {
-  boundary accounts create password -login-name $1 -password $DEFAULT_PASSWORD -auth-method-id $DEFAULT_AMPW
+  export BP="${DEFAULT_PASSWORD}"
+  boundary accounts create password -login-name $1 -password env://BP -auth-method-id $DEFAULT_AMPW
 }
 
 function read_account() {

internal/tests/cli/boundary/_credentials.bash

@@ -6,12 +6,13 @@ function create_username_password_credential() {
   local user=$3
   local pass=$4
   
+  export BP="${pass}"
   boundary credentials create username-password \
     -name $name \
     -description 'test username password credential' \
     -credential-store-id $sid \
     -username $user \
-    -password $pass
+    -password env://BP
 }
 
 function read_credential() {