fix: replace bare Option.get in getPortId with descriptive IllegalStateException

[Ma77Ball]

What changes were proposed in this PR?

AmberFIFOChannel.getPortId called this.portId.get on an Option[PortIdentity] that defaults to None. Calling getPortId before setPortId threw a bare NoSuchElementException with no message, giving callers no indication of which channel was misconfigured or what setup step was missed.

Replaced .get with .getOrElse(throw new IllegalStateException(...)) so the exception identifies the channel and points the caller at the missing setPortId call.

Any related issues, documentation, discussions?

Closes: #4818

How was this PR tested?

Updated the existing AmberFIFOChannelSpec test that covered this path — it previously asserted NoSuchElementException and now asserts IllegalStateException with message content checks ("portId has not been set" and the channel ID string). All 13 specs pass.

Was this PR authored or co-authored using generative AI tooling?

Co-Authored with Claude Opus 4.7 in compliance with ASF

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 42.68%. Comparing base (16d3c6a) to head (fbefa1a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #4978      +/-   ##
============================================
- Coverage     42.69%   42.68%   -0.01%     
  Complexity     2186     2186              
============================================
  Files          1031     1031              
  Lines         38111    38112       +1     
  Branches       4004     4004              
============================================
  Hits          16270    16270              
  Misses        20825    20825              
- Partials       1016     1017       +1     

Flag	Coverage Δ		*Carryforward flag
access-control-service	39.53% <ø> (ø)		Carriedforward from 16d3c6a
agent-service	33.72% <ø> (ø)		Carriedforward from 16d3c6a
amber	43.16% <100.00%> (-0.01%)	⬇️
computing-unit-managing-service	0.00% <ø> (ø)		Carriedforward from 16d3c6a
config-service	0.00% <ø> (ø)		Carriedforward from 16d3c6a
file-service	33.24% <ø> (ø)		Carriedforward from 16d3c6a
frontend	33.00% <ø> (ø)		Carriedforward from 16d3c6a
python	88.87% <ø> (ø)		Carriedforward from 16d3c6a
workflow-compiling-service	47.72% <ø> (ø)		Carriedforward from 16d3c6a

*This pull request uses carry forward flags. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.