Allow to set Frame buffer count for ESP32-cam through YAML config

**Describe the problem you have/What new integration you would like**

Some ESP32-cam have capability to have higher frame buffer (upto 2) for smoother stream. Currently, the source defines the fb_count to be 1 and theres no way to change it through the YAML config.

**Please describe your use case for this integration and alternatives you've tried:**

Define directly the frame buffer count in YAML config for more smoother stream

**Additional context**

None.

The issue names no source files or tests. Start by locating the ESP32-cam camera component and its YAML configuration entry, then verify that the configured frame-buffer count reaches camera setup and add coverage if a relevant test exists; done means YAML can select the requested count.

Written by the indexing model from the issue text.