[Bug]: ts_project error when srcs include parent/sibling files

[jbedard]

What happened?

When the ts_project(srcs) is passed files that do not belong to the current BUILD odd errors occur.

1. passing .ts from parent/sibling packages:

Previous, before 85d969e, tsc would output an error saying the .ts is outside the rootDor.

After 85d969e write_tsconfig computes the wrong path and tsc outputs an error saying the file doesn't exist instead.

2. passing .ts from subpackages

GUESS: tsc will not complain about the inputs but will most likely fail to write the outputs.

3. passing .d.ts from parent/sibling packages:

Previously: may have passed depending if the dts is already in the bindir (so no copy action is created)
Now: probably fails because the path is computed wrong

Version

All, the error changed after 85d969e

How to reproduce

jbedard@ebb4759