extend custom selection to date (#1357)

skyvern/forge/prompts/skyvern/custom-select.j2

@@ -50,4 +50,8 @@ Select History:
 ```
 {{ select_history }}
 ```
-{% endif %}
+{% endif %}
+Current datetime in UTC, YYYY-MM-DD HH:MM format:
+```
+{{ utc_datetime }}
+```

skyvern/forge/prompts/skyvern/opened-dropdown-confirm.j2

@@ -2,6 +2,7 @@ There is a screenshot from a part of a web HTML page. Help me confirm if it is a
 
 An open dropdown menu can be defined as:
   - At least one option is visible in the screenshot.
+  - A calendar view or date picker could be considered as an open dropdown menu.
   - Do not consider it an open dropdown menu if the only visible option displays a message like "No results" or "No match".
   - Do not consider it an open dropdown menu if the only visible element displays a placeholder like "Please select", "-", or "Select...".