chore(codeql): simplify redundant null-conditionals in StudentList

[rlorenzo]

What

StudentList.CreateStudentListFromStudentGradYears builds a Student inside an if (std.Student != null) guard, but three members still used std.Student?. / std?.Student?.:

ClassLevel = std.Student.StudentInfo?.ClassLevel,   // was std.Student?.StudentInfo?...
TermCode   = std.Student.StudentInfo?.TermCode,      // was std.Student?.StudentInfo?...
Active     = std.Student.Current == 1 || std.Student.Future == 1  // was std?.Student?...

The genuinely-nullable StudentInfo? is kept.

Why

CodeQL flagged these as cs/constant-condition (#634, #635, #636, #637) — always-non-null because the std.Student != null guard already holds and std comes from .First(). The ?. operators were dead. This is a behavior-neutral simplification, not a null-safety change.

Notes

• No behavior change; build/lint/tests green.
• A pre-existing nullable warning (CS8601) on the unrelated MailId line is out of scope for this PR.

[codecov-commenter]

Bundle Report

Bundle size has no change ✅

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.49%. Comparing base (f6dbe72) to head (b9db3a0).

Files with missing lines	Patch %	Lines
web/Areas/Students/Services/StudentList.cs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #222   +/-   ##
=======================================
  Coverage   44.49%   44.49%           
=======================================
  Files         895      895           
  Lines       51655    51655           
  Branches     4812     4812           
=======================================
  Hits        22983    22983           
  Misses      28108    28108           
  Partials      564      564           

Flag	Coverage Δ
backend	44.64% <0.00%> (ø)
frontend	41.32% <ø> (ø)

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[Copilot]

Pull request overview

This PR addresses CodeQL cs/constant-condition findings by removing redundant null-conditional operators inside StudentList.CreateStudentListFromStudentGradYears, where std.Student is already guarded by if (std.Student != null).

Changes:

• Simplify ClassLevel and TermCode assignments by removing redundant std.Student?. null-conditionals while preserving the genuinely nullable StudentInfo?.
• Simplify Active computation by removing redundant std?.Student?. null-conditionals under the existing std.Student != null guard.