Reformat DefaultAzureCredential flow chart (Azure#23222)

Author: scottaddie

sdk/azidentity/img/mermaidjs/DefaultAzureCredentialAuthFlow.md

@@ -1,18 +1,29 @@
 ```mermaid
 %% STEPS TO GENERATE IMAGE
 %% =======================
-%% 1. Install mermaid CLI (see https://github.com/mermaid-js/mermaid-cli/blob/master/README.md)
+%% 1. Install mermaid CLI v10.9.1 (see https://github.com/mermaid-js/mermaid-cli/blob/master/README.md):
+%%    npm i -g @mermaid-js/[email protected]
 %% 2. Run command: mmdc -i DefaultAzureCredentialAuthFlow.md -o DefaultAzureCredentialAuthFlow.svg
 
-flowchart LR;
-    A(Environment):::deployed ==> B(Workload Identity):::deployed ==> C(Managed Identity):::deployed ==> D(Azure CLI):::developer ==> E(Azure Developer CLI):::developer;
+%%{
+  init: {
+    'theme': 'base',
+    'themeVariables': {
+      'tertiaryBorderColor': '#fff',
+      'tertiaryColor': '#fff'
+    }
+  }
+}%%
 
+flowchart LR;
     subgraph CREDENTIAL TYPES;
         direction LR;
-        Deployed(Deployed service):::deployed --- Developer(Developer):::developer;
+        Deployed(Deployed service):::deployed ~~~ Developer(Developer):::developer;
+    end;
 
-        %% Hide links between boxes in the legend by setting width to 0. The integers after "linkStyle" represent link indices.
-        linkStyle 4 stroke-width:0px;
+    subgraph CREDENTIALS;
+        direction LR;
+        A(Environment):::deployed --> B(Workload Identity):::deployed --> C(Managed Identity):::deployed --> D(Azure CLI):::developer --> E(Azure Developer CLI):::developer;
     end;
 
     %% Define styles for credential type boxes