[FEATURE] Support proxy for Azure OpenAI Chat model

[Angappan95]

Describe the feature you'd like
Currently, I dont see support for connecting to Azure OpenAI services which is behind the Proxy layer. This is a limitation because many companies prefer this setup for security reasons.
To access a OpenAI service via proxy, users need to configure proxy details (domain, signature, and CA certificate) within the httpx client object when creating an AzureChatOpenAI model instance.
Integrating support for accessing Azure OpenAI with proxy configuration would be a valuable addition to Flowise.

[vincenzomanzoni]

I'm also interested in this topic. It is very common to run these kinds of applications in an enterprise context with HTTP-compatible proxies.