Drop the .NET in-process CAPI matrix cells blocked by CLI 1.0.81-2

The ubuntu and macOS `inprocess` + `capi` cells are the only .NET
combinations that fail on @github/copilot 1.0.81-2. A completed run
reported 241 failures across 43 classes and took 150-225 minutes,
which also starved the rest of the matrix of runners.

The defect is specific to this pairing: the in-process BYOK cells and
every stdio CAPI cell pass. Exclude just those two cells, mirroring
the existing Windows in-process exclusion above.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 812b44f2-ef93-4b32-b051-c7092f612279

Author: stephentoub

.github/workflows/dotnet-sdk-tests.yml

@@ -32,6 +32,16 @@ jobs:
           - os: windows-latest
             transport: default
             shard: full
+          # TODO(cli-1.0.81-2): @github/copilot 1.0.81-2 never completes a model-driven
+          # turn when the runtime is hosted in-process against the CAPI backend. A full
+          # run reported 241 failures across 43 classes and took 150-225 minutes, which
+          # also starved the rest of the matrix. The defect is specific to this pairing:
+          # the in-process BYOK cells below and the stdio capi cells are unaffected.
+          # Drop these two entries once a fixed CLI build is picked up.
+          - os: ubuntu-latest
+            transport: inprocess
+          - os: macos-latest
+            transport: inprocess
         include:
           # Keep xUnit serial within each process, but split the slow Windows
           # default-transport suite across two isolated test hosts. Keep both