Fix go to def for template spec modules

[shenglol]

The "Go to Definition" feature for template specs in VS Code is currently broken. When used, it opens the template spec JSON file in an editable state, though it should be read-only. This action then triggers the documentDidOpen event for the JSON file, which leads to a compilation update for the template spec module. As a result, the Bicep compiler mistakenly interprets the template spec JSON file as an ARM template, causing an The reference ARM template has errors message. This PR aims to fix that issue.

The problem was initially identified during the investigation of issue #14660. However, this PR might not fully resolve the issue, as according to the customer, the The reference ARM template has errors message can still appear randomly, even when "Go to Definition" is not used.

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 10500185948)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 10500185948

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 10500185948"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 10500185948

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 10500185948"

[github-actions]

Dotnet Test Results

    72 files   -     36      72 suites   - 36   23m 36s ⏱️ - 10m 3s
11 044 tests  -     19  11 044 ✅  -     19  0 💤 ±0  0 ❌ ±0 
25 864 runs   - 12 925  25 864 ✅  - 12 925  0 💤 ±0  0 ❌ ±0 

Results for commit 75113a9. ± Comparison against base commit e42fbe6.