do not spellcheck vendored scripts (#55020)

Summary:
While running `yarn spellcheck` I have spotted that scripts located in `/vendor` directory are checked, which lead to a lot of warnings in the output.

This PR adds an exclusion for the `/vendor` path in the spellcheck script which leads to way smaller warnings set and saves ~10s of runtime on my machine.

## Changelog:

[INTERNAL] [FIXED] - Add `/vendor` to excluded paths for spellcheck script.

Pull Request resolved: #55020

Test Plan: Running `yarn spellcheck` locally.

Reviewed By: cipolleschi

Differential Revision: D90104078

Pulled By: cortinico

fbshipit-source-id: 9c16a71616a13db1c217b917a498ff8f6a462799

Author: Simek

.github/workflow-scripts/analyze_scripts.sh

@@ -16,6 +16,7 @@ if [ -x "$(command -v shellcheck)" ]; then
     -type f \
     -not -path "*node_modules*" \
     -not -path "*third-party*" \
+    -not -path "*vendor*" \
     -name '*.sh' \
     -exec sh -c 'shellcheck "$1"' -- {} \;