fix: accept single-quoted string args in path functions (#1078)

[arimu1]

Summary

Fixes #1078

Path function argument parsing only treated double-quoted strings as JSON parameters. Single-quoted string args were dropped ($.concat('hello') → empty) or corrupted when mixed with path args ($.concat($.x,'-',$.y) → P-'Q). Filter predicates already accept single quotes.

Changes

• Treat SINGLE_QUOTE like a JSON parameter starter in PathCompiler.parseFunctionParameters
• Track the active quote delimiter (not a shared counter) so apostrophes inside double-quoted strings (e.g. "it's") still group correctly
• Normalize single-quoted string literals to double-quoted JSON before JsonProvider.parse, so strict providers (Jackson, Jakarta JSON, etc.) accept them

Tests

• NestedFunctionTest.testStringConcatWithSingleQuotedJSONParameter covers standalone, mixed path+literal, and double-quoted apostrophe cases across all configured providers

Test plan

• ./gradlew :json-path:test --tests com.jayway.jsonpath.internal.function.NestedFunctionTest.testStringConcatWithSingleQuotedJSONParameter (Temurin 21)
• ./gradlew :json-path:test full module suite (Temurin 21)

JsonPath.read("{}", "$.concat('hello')");                 // "hello"
JsonPath.read("{\"x\":\"P\",\"y\":\"Q\"}", "$.concat($.x,'-',$.y)"); // "P-Q"
JsonPath.read("{}", "$.concat(\"it's\")");                // "it's"