[iOS] Add force relay connection on iOS (#4928)

* [ios] Add a bogus test to check iOS behavior when setting environment variables

* [ios] Revert "Add a bogus test to check iOS behavior when setting environment variables"

This reverts commit 90ca01105a6b0f4471aac07a63fc95e5d4eaef9b.

* [ios] Add EnvList struct to export and import environment variables

* [ios] Add envList parameter to the iOS Client Run method

* [ios] Add some debug logging to exportEnvVarList

* Add "//go:build ios" to client/ios/NetBirdSDK files

client/ios/NetBirdSDK/env_list.go

@@ -0,0 +1,34 @@
+//go:build ios
+
+package NetBirdSDK
+
+import "github.com/netbirdio/netbird/client/internal/peer"
+
+// EnvList is an exported struct to be bound by gomobile
+type EnvList struct {
+	data map[string]string
+}
+
+// NewEnvList creates a new EnvList
+func NewEnvList() *EnvList {
+	return &EnvList{data: make(map[string]string)}
+}
+
+// Put adds a key-value pair
+func (el *EnvList) Put(key, value string) {
+	el.data[key] = value
+}
+
+// Get retrieves a value by key
+func (el *EnvList) Get(key string) string {
+	return el.data[key]
+}
+
+func (el *EnvList) AllItems() map[string]string {
+	return el.data
+}
+
+// GetEnvKeyNBForceRelay Exports the environment variable for the iOS client
+func GetEnvKeyNBForceRelay() string {
+	return peer.EnvKeyNBForceRelay
+}