revert: restore @shared alias imports in test executors

The @shared alias resolves correctly when tests are run from the tests/
directory via `pnpm test`, which is the canonical way to run them.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: nperez0111

tests/src/unit/shared/formatConversion/export/exportTestExecutors.ts

@@ -5,7 +5,7 @@ import {
   InlineContentSchema,
   StyleSchema,
 } from "@blocknote/core";
-import { addIdsToBlocks } from "../../../../../../shared/formatConversionTestUtil.js";
+import { addIdsToBlocks } from "@shared/formatConversionTestUtil.js";
 import { prettify } from "htmlfy";
 import { expect } from "vitest";
 

tests/src/unit/shared/formatConversion/exportParseEquality/exportParseEqualityTestExecutors.ts

@@ -9,7 +9,7 @@ import {
 import {
   addIdsToBlocks,
   partialBlocksToBlocksForTesting,
-} from "../../../../../../shared/formatConversionTestUtil.js";
+} from "@shared/formatConversionTestUtil.js";
 import { expect } from "vitest";
 
 import { ExportParseEqualityTestCase } from "./exportParseEqualityTestCase.js";