ui-settings: one address-format option per ss58 prefix

The address format list had an entry per network, and Pezkuwi, Zagros
and Bizinikiwi all use prefix 42, so it showed three options with the
same value; choosing one could not be told apart from the others.
prefixOptions keeps one option per prefix and lists every network
using it in its text. ui-settings gets the tsconfig.spec.json the
other packages with specs have, so the build leaves the spec out.

tsconfig.build.json

@@ -11,6 +11,7 @@
     { "path": "./packages/ui-keyring/tsconfig.build.json" },
     { "path": "./packages/ui-keyring/tsconfig.spec.json" },
     { "path": "./packages/ui-settings/tsconfig.build.json" },
+    { "path": "./packages/ui-settings/tsconfig.spec.json" },
     { "path": "./packages/ui-shared/tsconfig.build.json" },
     { "path": "./packages/ui-shared/tsconfig.spec.json" },
     { "path": "./packages/vue-identicon/tsconfig.build.json" }