libstore: Correct getUri methods for all stores

Previously `getUri` didn't include store query parameters,
`ssh-ng` didn't include any information at all and the local
store didn't have the path:

```
$ nix store info --store "local?root=/tmp/aaa&require-sigs=false"
Store URL: local
Version: 2.31.0
Trusted: 1
$ nix store info --store "ssh-ng://localhost?remote-program=nix-daemon"
Store URL: ssh-ng://
Version: 2.31.0
Trusted: 1
$ nix store info --store "ssh://localhost?remote-program=nix-store"
Store URL: ssh://localhost
```

This commit changes this to:

```
$ nix store info --store "local?root=/tmp/aaa&require-sigs=false"
Store URL: local?require-sigs=false&root=/tmp/aaa
Version: 2.31.0
Trusted: 1
$ nix store info --store "ssh-ng://localhost?remote-program=nix-daemon"
Store URL: ssh-ng://localhost?remote-program=nix-daemon
Version: 2.31.0
Trusted: 1
$ nix store info --store "ssh://localhost?remote-program=nix-store"
Store URL: ssh://localhost?remote-program=nix-store
```

src/libstore-tests/legacy-ssh-store.cc

@@ -6,21 +6,27 @@ namespace nix {
 
 TEST(LegacySSHStore, constructConfig)
 {
-    LegacySSHStoreConfig config{
+    initLibStore(/*loadConfig=*/false);
+
+    auto config = make_ref<LegacySSHStoreConfig>(
         "ssh",
-        "localhost",
+        "me@localhost:2222",
         StoreConfig::Params{
             {
                 "remote-program",
                 // TODO #11106, no more split on space
                 "foo bar",
             },
-        }};
+        });
+
     EXPECT_EQ(
-        config.remoteProgram.get(),
+        config->remoteProgram.get(),
         (Strings{
             "foo",
             "bar",
         }));
+
+    auto store = config->openStore();
+    EXPECT_EQ(store->getUri(), "ssh://me@localhost:2222?remote-program=foo%20bar");
 }
 } // namespace nix

src/libstore-tests/nix_api_store.cc

@@ -5,6 +5,7 @@
 
 #include "nix/store/tests/nix_api_store.hh"
 #include "nix/util/tests/string_callback.hh"
+#include "nix/util/url.hh"
 
 #include "store-tests-config.hh"
 
@@ -23,7 +24,13 @@ TEST_F(nix_api_store_test, nix_store_get_uri)
     std::string str;
     auto ret = nix_store_get_uri(ctx, store, OBSERVE_STRING(str));
     ASSERT_EQ(NIX_OK, ret);
-    ASSERT_STREQ("local", str.c_str());
+    auto expectedStoreURI = "local?"
+                            + nix::encodeQuery({
+                                {"log", nixLogDir},
+                                {"state", nixStateDir},
+                                {"store", nixStoreDir},
+                            });
+    ASSERT_EQ(expectedStoreURI, str);
 }
 
 TEST_F(nix_api_util_context, nix_store_get_storedir_default)

src/libstore-tests/ssh-store.cc

@@ -8,24 +8,31 @@ namespace nix {
 
 TEST(SSHStore, constructConfig)
 {
-    SSHStoreConfig config{
-        "ssh",
-        "localhost",
+    initLibStore(/*loadConfig=*/false);
+
+    auto config = make_ref<SSHStoreConfig>(
+        "ssh-ng",
+        "me@localhost:2222",
         StoreConfig::Params{
             {
                 "remote-program",
                 // TODO #11106, no more split on space
                 "foo bar",
             },
-        },
-    };
+        });
 
     EXPECT_EQ(
-        config.remoteProgram.get(),
+        config->remoteProgram.get(),
         (Strings{
             "foo",
             "bar",
         }));
+
+    auto store = config->openStore();
+    EXPECT_EQ(store->getUri(), "ssh-ng://me@localhost:2222?remote-program=foo%20bar");
+    config->resetOverridden();
+    store = config->openStore();
+    EXPECT_EQ(store->getUri(), "ssh-ng://me@localhost:2222");
 }
 
 TEST(MountedSSHStore, constructConfig)