Add examples for CurrentClamp* types to icephys tutorial

[ehennestad]

Motivation

Reach 100% tutorial coverage for NWB Types. Mirroring NeurodataWithoutBorders/pynwb#2004

How to test the behavior?

Run icephys tutorial

Checklist

• Have you ensured the PR description clearly describes the problem and solutions?
• Have you checked to ensure that there aren't other open or previously closed Pull Requests for the same change?
• If this PR fixes an issue, is the first line of the PR description fix #XX where XX is the issue number?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.16%. Comparing base (e070e20) to head (c0405c0).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #632   +/-   ##
=======================================
  Coverage   95.16%   95.16%           
=======================================
  Files         113      113           
  Lines        4734     4734           
=======================================
  Hits         4505     4505           
  Misses        229      229           

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---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[bendichter]

@ehennestad do you know why the tests are failing?

....... [�Warning: Unexpected properties {comment} for instance of type
"types.hdmf_common.VectorIndex" at file location "some/dataset/path"

NB: The properties in question were dropped while reading the file.

Consider checking the schema version of the file with
util.getSchemaVersion(filename) and comparing with the YAML namespace version
present in nwb-schema/core/nwb.namespace.yaml]�
[�> In io.createParsedType (line 51)
In tests.unit.io.testCreateParsedType>testCreateTypeWithInvalidInputs (line 29)]�
.......... ..........
.......... .........
Failure Summary:

   Name                                                            Failed  Incomplete  Reason(s)
  =============================================================================================================
   tests.unit.TutorialTest/testTutorial(tutorialFile=ecephys.mlx)    X                 Failed by verification.

results =

1x219 TestResult array with properties:

  Name
  Passed
  Failed
  Incomplete
  Duration
  Details

Totals:
218 Passed, 1 Failed, 0 Incomplete.
518.3087 seconds testing time.

{�Error using assert
At least one test failed in the test session.

Error in matlab.unittest.internal.BaseTestResult/assertSuccess (line 126)
assert(~any([resultArray.Failed]),message('MATLAB:unittest:TestResult:UnsuccessfulRun'));

Error in command_baf5e37b_dc26_43af_898e_2ecfad424951 (line 2)
results = assertSuccess(nwbtest);
}�