Escape LIKE wildcard chars correctly in SQL Server StartsWith(char)

[ilkertskn]

When string.StartsWith(char) is called with a LIKE wildcard ('%', '_' or '['), the SQL Server translator built the pattern with LikeEscapeChar + s + "%". Both operands of the first + are chars, so they are added numerically and the pattern becomes e.g. LIKE N'129%' instead of LIKE N'\%%' ESCAPE N'\'. The query runs but matches the wrong rows. EndsWith and Contains were already concatenating correctly.

Use string interpolation for both the constant and the parameter path, and add FunkyData tests covering the constant, parameter, bracket and negated cases.

Fixes #38923

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[ilkertskn]

The 7 failures are all in BatchingTest and cascade from a single connection-pool timeout in Deadlock_on_inserts_and_deletes_with_dependents_is_handled_correctly on the CI SQL Server. The deadlock test then aborted before Fixture.ReseedAsync(), leaving 4 extra blogs in the shared fixture database, which is exactly the off-by-4 (503 vs 499) and off-by-2 (4 vs 2) seen in the subsequent Inserts_* tests. None of these tests exercise LIKE translation; this PR only touches SqlServerSqlTranslatingExpressionVisitor and the FunkyData tests, which passed in the same run. Re-running the job should be enough. fyi

[AndriySvyryd]

Also change this for EndsWith and for any other ambiguous use of the + operator with a char

[Copilot]

Copilot review overview

🟡 Changes recommended

The constant wildcard path still emits unsupported ESCAPE SQL on Azure Synapse.

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Review effort: Lite
Findings: 1 · 1

Open (2)

• Avoid LIKE ESCAPE for char wildcards on Synapse · New
• Fix Synapse inherited test for char wildcard translation · New

What changed in this PR

Fixes SQL Server StartsWith(char) translation for LIKE wildcard characters and adds regression coverage.

Changes:

• Corrects constant and parameterized pattern construction.
• Adds shared wildcard and negated-case tests.
• Adds SQL Server SQL baselines.

File	Summary
test/​EFCore.SqlServer.FunctionalTests/​Query/​FunkyDataQuerySqlServerTest.cs	Adds SQL Server baselines.
test/​EFCore.Specification.Tests/​Query/​FunkyDataQueryTestBase.cs	Adds shared regression tests.
src/​EFCore.SqlServer/​Query/​Internal/​SqlServerSqlTranslatingExpressionVisitor.cs	Fixes wildcard pattern construction.