change environment effect on all open workspace

[zengLH1981]

• REST Client Version: v0.24.6
• VSCode Version: lasted
• OS Version: win 10

Steps to Reproduce:

1. open tow workspace ws1 ws2 ,and create tow same environment , such as sit , uat ,and some Variables
2. ws1 select sit
3. ws2 select uat
4. back to ws1, environment Variables use uat value, ws1 should keep sit .