fix(uniffi): stop shadowing tera-cli with an unrelated crate

The composite action pre-installed crates.io `tera-cli@0.5.0`, which is a
different project from chevdor/tera-cli and has a different CLI (`--env`,
no `--env-only`). Because it still provides a `tera` binary, cargo-make's
`tera --help` probe succeeded and the `install-tera` task never ran, so
swift-generate-manifest died on "Found argument '--env-only' which wasn't
expected" — reintroducing the bug #1238 had already fixed.

There is no binary distribution to pre-install: chevdor publishes as
`teracli`, and only up to 0.3.0. Drop the step and let `install-tera` build
from the pinned git tag (~30s).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: pblazej

.github/actions/uniffi-deps/action.yml

@@ -5,8 +5,3 @@ runs:
     - name: Install cargo-make
       uses: taiki-e/install-action@682e7d9e49c5e653d371fc6adbda67653461378a # v2.82.4
       with: { tool: cargo-make@0.37 }
-    - name: Install tera-cli
-      uses: taiki-e/install-action@682e7d9e49c5e653d371fc6adbda67653461378a # v2.82.4
-      with: { tool: tera-cli@0.5.0 }
-    # ^ This would be installed by the cargo-make file automatically, but this ensures
-    # it is already available and downloads binary distribution (no need to build from source).