Issue 562: Revise pattern:patternExpression to be object property, and test for error form

[ajnelson-nist]

This Pull Request resolves all requirements of Issue #562 .

Coordination

• [x] Pull Request is against correct branch
• [x] Pull Request is in, or reverted to, Draft status before Solutions Approval vote has passed
• [x] CI passes in UCO feature branch against develop-2.0.0
• [x] CI passes in UCO current unstable-2.0.0 branch (7dc3423)
• [x] CI passes in CASE current unstable-2.0.0 branch tracking UCO's unstable-2.0.0 as submodule (4aff9c9)
• [x] Impact on SHACL validation reviewed for CASE-Corpora
• [x] Impact on SHACL validation remediated for CASE-Corpora (N/A)
• [x] Impact on SHACL validation reviewed for CASE-Examples
• [x] Impact on SHACL validation remediated for CASE-Examples (N/A)
• [x] Impact on SHACL validation reviewed for casework.github.io
• [x] Impact on SHACL validation remediated for casework.github.io (N/A)
• [x] Milestone linked
• [x] Solutions Approval vote logged on corresponding Issue (once logged, can be taken out of Draft PR status)

[ajnelson-nist]

This PR is ready for review and merge.