TypeScript Extension Multiroot Support

[mjbvz]

Feature
Ensure that the TS extension works properly for multiroot workspaces

Items

• TS Version Selector for Multiroot Workspaces #30262 - Version selector
• TS Build Task Multiroot Support #30415 - TS build task support
• TS Server: means to open files in different inferred projects TypeScript#16961 - Different inferred project per folder

[mjbvz]

Moving out to august as we are waiting on microsoft/TypeScript#16961