Dont throw if optional dependency cannot be found

e2e/optional-dependencies/README.md

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+# optional-dependencies
+
+This project is used to end-2-end test how generate-license-file functions with optional
+dependencies that are not present on disk, such as in the case of platform specific dependencies,
+or deps that fail to install.
+
+To test this case we just install using `--omit=optional`, so the optionals don't appear on disk.

e2e/optional-dependencies/jest.config.js

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+/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
+module.exports = {
+  preset: "ts-jest",
+  testEnvironment: "node",
+  testMatch: ["**/*.spec.ts"],
+  testTimeout: 20000,
+};