feat: Add instance partition support to spanner instance proto (#2001)

* fix: Add client library version to headers
fix: Allow bundlers to bundle JSON files correctly for ESM
deps: Update dependency google-gax to ^4.3.1
fix: Export types from protos in ESM

PiperOrigin-RevId: 609821360

Source-Link: googleapis/googleapis@5c5ecf0

Source-Link: googleapis/googleapis-gen@b875fcd
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiYjg3NWZjZGQxNGI0ZGVmNjUyMTgyOTMwMDNkOWJlYzRiODQyZWNhNyJ9

* feat: Add instance partition support to spanner instance proto

PiperOrigin-RevId: 611127452

Source-Link: googleapis/googleapis@618d47c

Source-Link: googleapis/googleapis-gen@92d8555
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiOTJkODU1NTg4ODI4NDMwZThiNDI4ZWQ3ODIxOWUyM2VlNjY2ZGE3OCJ9

* feat: add SpannerExecutorProxyClient to index.ts

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.gitignore

@@ -12,5 +12,3 @@ system-test/*key.json
 .DS_Store
 package-lock.json
 __pycache__
-.idea
-.vscode