Add (an) "expression could be simplified" linter(s)

**Is your feature request related to a problem? Please describe.**
A Bicep expression may be technically correct but indirect or inefficient (e.g., ` || true` or ` ?? null` or `contains(obj, 'property') ? obj.property : null`).

**Describe the solution you'd like**
One or more linters could scan for known patterns and propose fixes, similar to [Roslyn linters in the "Unnecessary code rules" category](https://learn.microsoft.com/en-us/dotnet/fundamentals/code-analysis/style-rules/language-rules#expression-level-preferences).

Start by reviewing the requested simplification patterns in the issue and the linked Roslyn “Unnecessary code rules” category. Define the linter scope, supported diagnostics, and proposed fixes before identifying the relevant Bicep analysis entry points; done means the selected patterns are detected consistently and their fixes are validated.

Written by the indexing model from the issue text.