Add try-catch to avoid failing requests

On GHES servers below version 3.8, the variables context is unavailable, resulting in 404 errors when calling the corresponding endpoint.

languageserver/src/context-providers/variables.ts

@@ -2,9 +2,10 @@ import {data, DescriptionDictionary} from "@actions/expressions";
 import {Pair} from "@actions/expressions/data/expressiondata";
 import {StringData} from "@actions/expressions/data/index";
 import {WorkflowContext} from "@actions/languageservice/context/workflow-context";
-import {warn} from "@actions/languageservice/log";
+import {log, warn} from "@actions/languageservice/log";
 import {isMapping, isString} from "@actions/workflow-parser";
 import {Octokit} from "@octokit/rest";
+import {RequestError} from "@octokit/types";
 
 import {RepositoryContext} from "../initializationOptions";
 import {TTLCache} from "../utils/cache";
@@ -42,6 +43,7 @@ export async function getVariables(
   }
 
   const variablesContext = defaultContext || new DescriptionDictionary();
+  try {
     const variables = await getRemoteVariables(octokit, cache, repo, environmentName);
 
     // Build combined map of variables
@@ -86,6 +88,13 @@ export async function getVariables(
       .forEach(variable => variablesContext?.add(variable.key, variable.value, variable.description));
 
     return variablesContext;
+  } catch (e: any) {
+    const requestError: RequestError = e;
+    if (requestError.name == "HttpError" && requestError.status == 404) {
+      log("Failure to request variables. Ignore if you're using GitHub Enterprise Server below version 3.8");
+      return variablesContext;
+    } else throw e;
+  }
 }
 
 export async function getRemoteVariables(