fix(tapis): tolerate empty-string parameter bindings

[mosoriob]

Summary

• POST /executionEngines/tapis crashed with Cannot read properties of undefined (reading 'match') whenever a model input parameter had no default and the user-supplied binding was an empty string. The regex check at helpers.ts:112 ran on undefined.
• The original error was then masked by a secondary crash in handleSubmissionFailure because this.seeds was never initialized when seedExecutions threw before assignment, so this.seeds.length blew up too. The DB cleanup mutation never ran.

Fix

• Guard the geojson regex in getInputsParameters with optional chaining (parameters[ip.id]?.match(...)).
• Initialize this.seeds = [] at the top of submitExecutions so the failure path in handleSubmissionFailure always has a valid array.
• Add unit tests in tapis/tests/helpers.test.ts covering: empty-string binding without default, populated binding, and ip.value default fallback.

Repro

Input that triggered the original 500:

bindings: {
  '...0d626932...': <Object>,
  '...4103a17f...': ''
}

With this fix the empty parameter is left unset (downstream Tapis layer can decide), the submission either succeeds or fails with a clear error, and the failure cleanup mutation always runs.

Test plan

• npx jest src/classes/tapis -> 17/17 pass
• npm run build -> webpack compiled successfully
• Manual: re-submit the failing ensemble against a deployed image and confirm the 500 is gone (and that any real downstream failure surfaces with its actual message)