fix: skip assertion tracking injection for namespace function calls

[TwitchBronBron]

Summary

• Fixes a bug where calls like some.space.assertEqual(...) inside a test method incorrectly had assertion tracking (currentAssertLineNumber, currentResult?.isFail, done()) injected using some.space as the target object
• Adds a namespace guard in TestGroup.modifyAssertions(): if the first part of the call path is a known namespace name, the call is a namespaced function (not a method on an object like m) and assertion tracking injection is skipped

Background

When a test contains a namespaced function call whose name matches the assertion regex (e.g. some.space.assertEqual(...)), the rewriter was computing callPath = "some.space" and injecting:

some.space.currentAssertLineNumber = 29
some_space_assertEqual(...)
if some_space_currentResult_isFail = true then ...

The bug was latent in Rooibos but became visible after BrighterScript 0.72.0 made namespace recognition more reliable during transpile (via the new ScopeNamespaceLookup), causing some.space in the injected code to be correctly transpiled to some_space..

Test plan

• New regression test in plugin.spec.ts verifies that some.space.assertEqual(1, 1) inside a test method does NOT produce some_space.currentAssertLineNumber, while m.assertEqual(2, 2) still correctly gets m.currentAssertLineNumber injected
• All 121 existing tests pass

🤖 Generated with Claude Code