Introduce relational EF.Functions.JsonPathExists

[roji]

As part of syncing EFCore.PG, I noticed that the new EF.Functions.JsonExists introduced in #31136 (preview.2) conflicts with an existing function in EFCore.PG, which takes a key name (not a jsonpath). In addition, both the PG and SQL Server functions are actually called jsonb_path_exists()/JSON_PATH_EXISTS(), and including "path" in the name makes it more explicit that the argument represents a jsonpath rather than a simple property/key. The other databases also diverge quite widely around this, so while the capability exists everywhere, it's named differently.

So this PR renames EF.Function.JsonExists to JsonPathExists.

Database	Function
PG	jsonb_path_exists
SQL Server	JSON_PATH_EXISTS (since SQL Server 2022)
SQLite	json_type (returns NULL for non-existing path, as opposed to 'null' for JSON null values)
MariaDB	JSON_EXISTS
MySQL	JSON_CONTAINS_PATH
Oracle	JSON_EXISTS

Part of #31136

[Copilot]

Pull request overview

This PR renames the relational JSON path existence function from EF.Functions.JsonExists to EF.Functions.JsonPathExists to avoid name conflicts (notably with EFCore.PG) and to clarify that the argument is a JSONPath rather than a simple key.

Changes:

• Renamed the public API RelationalDbFunctionsExtensions.JsonExists to JsonPathExists.
• Updated SQL Server and SQLite translation visitors to recognize/translate the new method name.
• Renamed/updated relational and provider functional tests to use JsonPathExists and updated expected SQL baselines.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/EFCore.Sqlite.FunctionalTests/Query/Translations/JsonTranslationsSqliteTest.cs	Renames overridden test methods and base calls to JsonPathExists_* and keeps SQLite SQL assertions aligned.
test/EFCore.SqlServer.FunctionalTests/Query/Translations/JsonTranslationsSqlServerTest.cs	Renames overridden test methods and base calls to JsonPathExists_* and keeps SQL Server SQL assertions aligned.
test/EFCore.Relational.Specification.Tests/Query/Translations/JsonTranslationsRelationalTestBase.cs	Renames the relational JSON translation tests and updates LINQ to call EF.Functions.JsonPathExists.
src/EFCore.Sqlite.Core/Query/Internal/SqliteSqlTranslatingExpressionVisitor.cs	Updates method-name dispatch to translate JsonPathExists.
src/EFCore.SqlServer/Query/Internal/SqlServerSqlTranslatingExpressionVisitor.cs	Updates method-name dispatch to translate JsonPathExists.
src/EFCore.Relational/Extensions/RelationalDbFunctionsExtensions.cs	Public API rename from JsonExists to JsonPathExists.

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.