Fix launch server breaking when no proxy option is passed.

[AgnayS]

Problem

When launching Camoufox server without a proxy, the following error occurs:
Error launching server: proxy: expected object, got null

Root Cause

The launch_options() function always includes "proxy": proxy in the returned dictionary, even when proxy=None. When serialized to JSON and
passed to Playwright's launchServer(), this becomes "proxy": null, which Playwright rejects.

Solution

Only include the proxy key in the returned options when proxy is not None. This matches Playwright's expectation that the proxy parameter
should either be a valid object or completely absent.

Changes

• Modified the return statement in launch_options() to conditionally include proxy
• Added conditional logic to exclude None proxy values
• No breaking changes - existing code continues to work