Add "Bytes Remaining" to the selectable signal/metric when configuring alerts

[GlenGengMicrosoft]

Hi Azure monitor team,

I am trying to open this issue on behalf of our customer. The customer would like to be alerted when the bytes remaining in a file sync session is too large. Please refer below:

However, when configuring, this metric is not selectable:

Please kindly advise and discuss if we would have some solution/workaround on this.