frontend: clarify Video configuration's "Allowed WebRTC remote IP Address" info

### Current behaviour

When setting up a video stream to cockpit, the user must setup the Settings / Video configuration but I think we should improve the "info" description for the "Allowed WebRTC remote IP Addresses" field.

I think the instructions should be more specific about which device's IP addresses should be placed in the field. The current instructions are copied below but I'm wondering, which component's "interface" (aka IP address) are we talking about? The RPI? the user's PC? the camera? something else? Also let's use the most specific word possible and not use multiple words that mean the same thing. So for example, let's not use both "interface" and "IP address". if we're looking for an IP address, let's just say "IP address" because it is the more specific term.

`Select the IP addresses to allow connecting to for WebRTC video streaming. For best performance it is recommended to only use the most reliable interfaces - e.g. avoid wireless interfaces if there is a tethered/wired interface available. If no value is specified, all available routes are allowed.`

From a discussion with @Williangalvani it seems like this field refers to the IP address of the RPI. I wonder if it would be possible to put the name of the network interface beside the IP address? Eg. "ETH0", "WLAN"? That might make it easier for users to know which IP address is for which network interface / link.

### Expected or desired behaviour

Instructions that allow the user to more quickly understand what should be placed in the field

### Prerequisites

- [x] I have checked to make sure that a similar request has not already been filed or fixed.

Locate the Video configuration UI and the info text for the “Allowed WebRTC remote IP Addresses” field. Review the existing wording and the discussion about the RPI address and network-interface names; done means the instructions clearly identify which IP addresses belong there and use consistent terminology.

Written by the indexing model from the issue text.