test(knex): fix TAV tests for knex

[trentm]

knex version 3.2.0 to 3.2.7 (inclusive) includes an "exports"
in package.json that broke deep-package imports. That was reverted
in 3.2.8, because apparently there are some use cases for knex
users doing deep package imports.

In our case, we were doing require('knex/package') in tests only
for getting the package version. While the "exports" existed there
was a mapping for "./package.json", so the workaround for us is simple.

Refs: knex/knex#6422

---

TAV tests for knex are failing on knex@3.2.7.
E.g. https://github.com/elastic/apm-agent-nodejs/actions/runs/25679762074/job/75392718232#step:3:307

node_tests-1  | -- installing ["knex@3.2.7"]
node_tests-1  | -- running test "node test/instrumentation/modules/pg/knex.test.js" with knex (env: {})
node_tests-1  | node:internal/modules/cjs/loader:657
node_tests-1  |       throw e;
node_tests-1  |       ^
node_tests-1  | 
node_tests-1  | Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './package' is not defined by "exports" in /app/node_modules/knex/package.json
node_tests-1  |     at exportsNotFound (node:internal/modules/esm/resolve:314:10)
node_tests-1  |     at packageExportsResolve (node:internal/modules/esm/resolve:661:9)

Local repro:

npm run docker:start postgres
TAV=knex npx tav

[github-actions]

🤖 GitHub comments

Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[trentm]

/test tav knex