fix: fixing missing read parent

[jacek-prisma]

This fixes a problem with MySQL flavour when the foreign key relation mode is used with the query compiler. In this scenario our update node in the query graph ends up having no prior read node. The read node is necessary for databases that don't support RETURNING. The query engine has a workaround for it which involves issuing queries dynamically at runtime whenever selectors for an update are missing but we can't do that in the query compiler workflow. I've modified how the graph is constructed to always add a read node prior to the update. I've also included a minor optimization for the case when relation mode is set to prisma (to avoid introducing a performance regression) - we avoid issuing a read query when insert_emulated_on_update connects no edges to it.

[github-actions]

WASM Query Engine file Size

Engine	This PR	Base branch	Diff
Postgres	2.185MiB	2.185MiB	217.000B
Postgres (gzip)	875.186KiB	875.252KiB	-68.000B
Mysql	2.150MiB	2.150MiB	168.000B
Mysql (gzip)	859.988KiB	860.088KiB	-103.000B
Sqlite	2.059MiB	2.059MiB	220.000B
Sqlite (gzip)	825.145KiB	825.212KiB	-69.000B
SQL Server	2.115MiB	2.115MiB	220.000B
SQL Server (gzip)	848.294KiB	848.223KiB	73.000B

[codspeed-hq]

CodSpeed Performance Report

Merging #5497 will not alter performance

_{Comparing fix/read-parent-fix-test (a2b4da8) with main (63298ba)}

Summary

✅ 11 untouched benchmarks