ci: fix pnpm exec version check in npm publish workflow (#35156)
The "Test pnpm local install deno (with postinstall)" step in the npm
publish workflow failed on the v2.8.3 release (run 27359928517) even though the
package installed and ran correctly. pnpm 11.5.3's `pnpm exec` now
prints lockfile/supply-chain verification messages to stdout before the command
output, so the captured `deno -v` output no longer exactly equals
"deno <version>". Compare only the last line of the output instead.
