Avoid hard-coding extension ID except in package.json

[radeksimko]

Problem Statement

Currently we have the extension ID hard-coded in a number of places:

vscode-terraform/src/extension.ts

Line 15 in d79aeca

const extensionId = 'hashicorp.terraform';

vscode-terraform/src/test/helper.ts

Line 26 in d79aeca

const ext = vscode.extensions.getExtension('hashicorp.terraform');

vscode-terraform/src/test/workspaces.test.ts

Line 6 in d79aeca

const ext = vscode.extensions.getExtension('hashicorp.terraform');

Additionally in some places we relatedly use the global vscode.extensions API which we shouldn't need to use given that this is mainly designed for accessing APIs of other extensions and our code should be testable without relying on such high-level API.

This prevents us from re-publishing the extension easily under a different name or a publisher and also makes it difficult to run tests in such circumstances. Lastly it forces us to effectively write E2E tests for code that can otherwise be just unit-tested in isolation.

This is a pre-requisite for #774

Expected Maintainer Experience

• Maintainer is able to run tests regardless of any particular name or publisher values in package.json
• It is sufficient to replace fields in package.json to enable publishing of a different build or testing in a "sandbox" publisher

Proposal

• VSCode provides vscode.ExtensionContext as part of the activate() call, which itself already provides access to the extension itself. We can use this to pull out the extension ID + version dynamically from package.json where necessary (e.g. for telemetry reporting)
• For tests we can decouple the code that needs to be tested into existing/separate files, so that it becomes importable and testable without having to go through the whole extension activation lifecycle

[jpogran]

We can also move the telemetry key to the package.json file and access it with typescript magic context.extension.packageJSON.apiKey

[jpogran]

The context.extension property was added in 1.55: https://code.visualstudio.com/updates/v1_55#_new-extension-property-on-extensioncontext.

Extension authors can now use the new extension property on ExtensionContext, which is passed into the extension's activate function. This returns the same Extension instance that vscode.extensions.getExtension() returns, which contains properties such as the extension's ID, version, and a serialized packageJSON property where you can access data directly from your extension's package.json file.

We'll have to bump our minimum version of VS Code from 1.52.0 to 1.55.0 in order to use this property instead of vscode.extensions.getExtension(<extension-id>)

[github-actions]

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