Add pattern for variable tag in tiptap (#16652)

Since we now store rich text value in blocknote rather than markdown,
variables need to be resolved accordingly.

Replacing the variable tag pattern
`{"type":"variableTag","attrs":\{"variable":"(\{\{[^{}]+\}\})"\}\}` by a
blocknote text `{"type":"text","text":"${escapedText}"}`

Fixes https://github.com/twentyhq/twenty/issues/16583

To test :
- build a workflow that creates a note/ sends an email with a variable
in the body
- make sure the result is properly formatted once run

---------

Co-authored-by: cubic-dev-ai[bot] <191113872+cubic-dev-ai[bot]@users.noreply.github.com>

packages/twenty-shared/src/utils/evalFromContext.ts

@@ -0,0 +1,24 @@
+import Handlebars from 'handlebars';
+
+export const evalFromContext = (
+  input: string,
+  context: Record<string, unknown>,
+) => {
+  try {
+    Handlebars.registerHelper('json', (input: string) => JSON.stringify(input));
+
+    const inputWithHelper = input
+      .replace('{{', '{{{ json ')
+      .replace('}}', ' }}}');
+
+    const inferredInput = Handlebars.compile(inputWithHelper)(context, {
+      helpers: {
+        json: (input: string) => JSON.stringify(input),
+      },
+    });
+
+    return JSON.parse(inferredInput);
+  } catch {
+    return undefined;
+  }
+};