Crash if LSP settings missing `enableDiagnostics` key

[notpeter]

Bug description

Since https://github.com/prisma/language-tools/pull/1828 (@prisma/language-server >= "6.8.0") prisma-language-server crashes on startup with an empty settings -- or more specifically, any settings which does not provide enableDiagnostics.

How to reproduce

Steps to reproduce the behavior:

1. Launch Zed
2. Install Zed Prisma extension v0.1.0
3. Open a .prisma file
4. From the command palette (cmd-shift-p) spawn dev: language server logs
5. Select 'prisma-language-server' from the dropdown
6. In the server-logs, note:

Default version of Prisma 'prisma-schema-wasm': 2060c79ba17c6bb9f5823312b6f6b7f4a845738e
Extension name @prisma/language-server with version 6.8.2
Prisma Engines version: 6.8.0-43.2060c79ba17c6bb9f5823312b6f6b7f4a845738e
Prisma CLI version: 6.8.2
Configuration changed.
/Users/peter/Library/Application Support/Zed/extensions/work/prisma/node_modules/@prisma/language-server/dist/server.js:151
        if (settings.enableDiagnostics === false) {
                     ^

TypeError: Cannot read properties of null (reading 'enableDiagnostics')
    at validateTextDocument (/Users/peter/Library/Application Support/Zed/extensions/work/prisma/node_modules/@prisma/language-server/dist/server.js:151:22)
    at async /Users/peter/Library/Application Support/Zed/extensions/work/prisma/node_modules/@prisma/language-server/dist/server.js:162:9

Node.js v23.11.0

Workaround is to explicitly provide "enableDiagnostics": true via LSP settings.

Expected behavior

prisma-language-server does not crash with empty settings.

Prisma information

https://github.com/prisma/language-tools/blob/2390773013288b242d97bca5762d5320d95619ee/packages/language-server/src/server.ts#L157-L160

Environment & setup

• OS: macOS
• Editor: Zed
• Editor version: v0.189.x nightly, Prisma extension v0.1.0.
• @prisma/language-server: "6.8.2"

[ccssmnn]

i have this problem as well using the prisma LSP in helix