[pgAdmin4][Patch]: number.toFixed is not function

Hi

Please find the patch
*Issue:*
We got the following error in console log
*"number.toFixed is not function"*

*Steps to reproduce:*
1) Click on statistics tab.
1) Select any database node.
2) then select Databases collection node.
3) The above error will appear into console.

*Reason:*
I discussed the issue with @Murtaza and here we are explicitly
converting values at server side to string as JSON do not directly
support NaN & Infinity values. Because of which NumberFormatter receives
values of type string and breaks.

*Solution:*
Overrides the NumberFormatter to support NaN & Infinity values.
and we need to parse the values again in float at client side.

Please review.

Thanks,
Surinder Kumar