Handle the case when source parameters + render parameters are both e…

…mpty (#1218)

**Related Ticket:** #1028 

### Description of Changes
- It turns out that there are datasets (such as globalscope bluetarp)
that should not have any titiler parameters.
Bluetarp data from stac backend:
https://staging.openveda.cloud/api/stac/collections/blue-tarp-planetscope

### Notes & Questions About Changes
This makes me wonder about if we can validate anything about render
parameters - ex. When there is no render parameter at all from stac
back-end points, is there any way to be sure that this dataset is meant
to be without render parameters ? - Tagging @smohiudd for this question.

### Testing
Test this branch with veda-config's globalscope bluetarp dataset.

app/scripts/components/exploration/data-utils-no-faux-module.ts

@@ -17,7 +17,6 @@ import {
   DATA_METRICS,
   DEFAULT_DATA_METRICS
 } from './components/datasets/analysis-metrics';
-import { DEFAULT_COLORMAP } from './components/datasets/colormap-options';
 import { utcString2userTzDate } from '$utils/date';
 import {
   DatasetLayer,
@@ -64,8 +63,8 @@ function getInitialMetrics(data: DatasetLayer): DataMetric[] {
   return foundMetrics;
 }
 
-function getInitialColorMap(dataset: DatasetLayer): string {
-  return dataset.sourceParams?.colormap_name ?? DEFAULT_COLORMAP;
+function getInitialColorMap(dataset: DatasetLayer): string|undefined {
+  return dataset.sourceParams?.colormap_name;
 }
 
 export function reconcileDatasets(
@@ -194,6 +193,10 @@ export function resolveRenderParams(
   datasetSourceParams: Record<string, any> | undefined,
   queryDataRenders: Record<string, any> | undefined
 ): Record<string, any> | undefined {
+  // Return null if there are no user-configured sourcparams nor render parameter
+  // so it doesn't get subbed with default values
+  if (!datasetSourceParams && !queryDataRenders) return undefined;
+
   // Start with sourceParams from the dataset.
   // Return the source param as it is if exists
   if (hasValidSourceParams(datasetSourceParams)) {