Not able to fetch OpenTelemetry environment variables in React app & facing CORS issue on OTEL_EXPORTER_OTLP_ENDPOINT

[waqarahmed0340]

Issue Details:
I’m working on integrating OpenTelemetry with my React application. However, I’m facing two key challenges:

1. I am unable to retrieve the OpenTelemetry environment variables (e.g., OTEL_EXPORTER_OTLP_ENDPOINT) from the .NET Aspire resources dashboard in my React app.
2. When I configure the frontend OpenTelemetry setup and try to hit the OTEL_EXPORTER_OTLP_ENDPOINT (https://localhost:21216/), I encounter a CORS issue

The Frontend side code is below. Right now in this code, I am using the hard-coded values.
`import { WebTracerProvider } from "@opentelemetry/sdk-trace-web";
import {
ConsoleSpanExporter,
SimpleSpanProcessor,
BatchSpanProcessor,
} from "@opentelemetry/sdk-trace-base";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-http";
import { DocumentLoadInstrumentation } from "@opentelemetry/instrumentation-document-load";
import { FetchInstrumentation } from "@opentelemetry/instrumentation-fetch";
import { XMLHttpRequestInstrumentation } from "@opentelemetry/instrumentation-xml-http-request";
import { registerInstrumentations } from "@opentelemetry/instrumentation";
import { Resource } from "@opentelemetry/resources";
import { SemanticResourceAttributes } from "@opentelemetry/semantic-conventions";
import { ZoneContextManager } from "@opentelemetry/context-zone";

const provider = new WebTracerProvider({
resource: new Resource({
[SemanticResourceAttributes.SERVICE_NAME]: "multifamilyportal",
}),
});

provider.addSpanProcessor(
new SimpleSpanProcessor(
new OTLPTraceExporter({
url: https://localhost:21216/v1/traces,

}),

),
);

provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter()));

provider.register({
contextManager: new ZoneContextManager(),
});

registerInstrumentations({
instrumentations: [
new DocumentLoadInstrumentation(),
new FetchInstrumentation(),
new XMLHttpRequestInstrumentation(),
],
});

export const tracer = provider.getTracer("react-client-tracer");
`