refactor(@angular-devkit/architect-cli): remove rxjs as a dependency

`rxjs` was only a dependency for the `tap` operator which can be replaced
by accessing the result object returned from awaiting the builder output
`Observable` which is already converted to a Promise.

packages/angular_devkit/architect_cli/BUILD.bazel

@@ -24,7 +24,6 @@ ts_library(
         "@npm//@types/progress",
         "@npm//@types/yargs-parser",
         "@npm//ansi-colors",
-        "@npm//rxjs",
     ],
 )
 

packages/angular_devkit/architect_cli/bin/architect.ts

@@ -14,7 +14,6 @@ import { NodeJsSyncHost, createConsoleLogger } from '@angular-devkit/core/node';
 import * as ansiColors from 'ansi-colors';
 import { existsSync } from 'fs';
 import * as path from 'path';
-import { tap } from 'rxjs/operators';
 import yargsParser, { camelCase, decamelize } from 'yargs-parser';
 import { MultiProgressBar } from '../src/progress';
 
@@ -151,9 +150,7 @@ async function _executeTarget(
 
   // Wait for full completion of the builder.
   try {
-    const { success } = await run.output
-      .pipe(
-        tap((result) => {
+    const result = await run.output.toPromise();
     if (result.success) {
       parentLogger.info(colors.green('SUCCESS'));
     } else {
@@ -164,14 +161,11 @@ async function _executeTarget(
     parentLogger.info('\nLogs:');
     logs.forEach((l) => parentLogger.next(l));
     logs.splice(0);
-        }),
-      )
-      .toPromise();
 
     await run.stop();
     bars.terminate();
 
-    return success ? 0 : 1;
+    return result.success ? 0 : 1;
   } catch (err) {
     parentLogger.info(colors.red('ERROR'));
     parentLogger.info('\nLogs:');

packages/angular_devkit/architect_cli/package.json

@@ -18,7 +18,6 @@
     "@angular-devkit/core": "0.0.0-PLACEHOLDER",
     "ansi-colors": "4.1.3",
     "progress": "2.0.3",
-    "rxjs": "6.6.7",
     "symbol-observable": "4.0.0",
     "yargs-parser": "21.0.1"
   },