.NET Workflows - Add unit tests for EditTableExecutorAction (Declarative Workflows)

[Copilot]

Motivation and Context

WorkflowFormulaState automatically calls Bind() in its constructor, syncing variables to the PowerFx engine. Explicit State.Bind() calls after State.Set() were redundant in most test cases.

Description

When Bind() is needed:
Only when variables set via State.Set() will be referenced in PowerFx expressions during test execution:

this.State.Set("NewId", FormulaValue.New(10));
this.State.Bind(); // Required: NewId used in expression below
ValueExpression.Expression("{id: Local.NewId}")

When Bind() is not needed:
After State.Set() calls where variables aren't used in subsequent expressions - the constructor already bound initial state.

Kept one necessary State.Bind() in AddWithExpressionAsync with explanatory comment.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[Copilot]

Pull request overview

Adds a dedicated unit test suite for the declarative workflow EditTableExecutor, validating expected state updates across supported TableChangeType operations and a few key failure/edge scenarios.

Changes:

• Introduces EditTableExecutorTest coverage for Add/Remove/Clear/TakeFirst/TakeLast behaviors, including empty-table cases.
• Adds negative tests for invalid model construction and non-table variables, plus a remove-with-non-table-value scenario.