chore(ci): prevent downloads of Tact from npm in tact-template tests

[novusnota]

Current approach:

• Clone the repo
• Remove the tact from dependency list and run yarn install
• Then, use yarn link @tact-lang/compiler to install the local version of Tact compiler

Previous attempt:

In a regular install optionalDependencies are also being installed. That is, running yarn install will install Tact compiler inside the tact-template folder.

However, running yarn install --ignore-optional won't, which is precisely what we need — instead of downloading Tact from npm we'll link it with the built version from the repo.

Issue

Towards #1810 (only resolves the tact-template part)

Checklist

• I have run the linter, formatter and spellchecker
• I did not do unrelated and/or undiscussed refactorings