Surface SDK version info from channel into StoreInfo

[jleibs]

Some portion of the encoded rerun stream includes version information.

We use this to produce errors like:

Found log stream with Rerun version 0.15.1, which is incompatible with the local Rerun version 0.16.0-alpha.3. Loading will try to continue, but might fail in subtle ways.

However, once we process that info it disappears. Would be nice for this data to make it into the StoreInfo so we can show it in the UI.

If the stream info isn't the right place to put this, maybe it's a similar version number we should be adding to StoreInfo at store-creation time. (Related: #6281)