fix: check for peerDependenciesMeta in pkgIsLeaf to fix non-determinism (#6112)

close #5106

.changeset/lazy-brooms-search.md

@@ -0,0 +1,6 @@
+---
+"@pnpm/resolve-dependencies": patch
+pnpm: patch
+---
+
+Fix a case of installs not being deterministic and causing lockfile changes between repeat installs. When a dependency only declares `peerDependenciesMeta` and not `peerDependencies`, `dependencies`, or `optionalDependencies`, the dependency's peers were not considered deterministically before.

pkg-manager/resolve-dependencies/src/resolveDependencies.ts

@@ -1377,7 +1377,10 @@ function getMissingPeers (pkg: PackageManifest) {
 function pkgIsLeaf (pkg: PackageManifest) {
   return isEmpty(pkg.dependencies ?? {}) &&
     isEmpty(pkg.optionalDependencies ?? {}) &&
-    isEmpty(pkg.peerDependencies ?? {})
+    isEmpty(pkg.peerDependencies ?? {}) &&
+    // Package manifests can declare peerDependenciesMeta without declaring
+    // peerDependencies. peerDependenciesMeta implies the later.
+    isEmpty(pkg.peerDependenciesMeta ?? {})
 }
 
 function getResolvedPackage (