Bugfix: Use API's default value for enableEndpointIndependentMapping (#8600) (#15478)

Instead of using a hardcode default of `false` for
`enableEndpointIndependentMapping`, use the default value from the API.

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

.changelog/8600.txt

@@ -0,0 +1,4 @@
+```release-note:bug
+compute: used APIs default value for field `enable_endpoint_independent_mapping` in resource `google_compute_router_nat`
+
+```

google/services/compute/resource_compute_router_nat.go

@@ -247,10 +247,10 @@ Mutually exclusive with enableEndpointIndependentMapping.`,
 			},
 			"enable_endpoint_independent_mapping": {
 				Type:     schema.TypeBool,
+				Computed: true,
 				Optional: true,
-				Description: `Specifies if endpoint independent mapping is enabled. This is enabled by default. For more information
-see the [official documentation](https://cloud.google.com/nat/docs/overview#specs-rfcs).`,
-				Default: true,
+				Description: `Enable endpoint independent mapping.
+For more information see the [official documentation](https://cloud.google.com/nat/docs/overview#specs-rfcs).`,
 			},
 			"icmp_idle_timeout_sec": {
 				Type:        schema.TypeInt,

website/docs/r/compute_router_nat.html.markdown

@@ -280,8 +280,8 @@ The following arguments are supported:
 
 * `enable_endpoint_independent_mapping` -
   (Optional)
-  Specifies if endpoint independent mapping is enabled. This is enabled by default. For more information
-  see the [official documentation](https://cloud.google.com/nat/docs/overview#specs-rfcs).
+  Enable endpoint independent mapping.
+  For more information see the [official documentation](https://cloud.google.com/nat/docs/overview#specs-rfcs).
 
 * `region` -
   (Optional)