[dev-server][xdl] suppress remote debugging EISDIR error

[Kudo]

Why

facebook/react-native#28844
Close ENG-2007

How

prepending a middleware in metro and return 404 for /debugger-ui/*.map requests

Test Plan

initialize a sdk43 project. launch app, enable remote debugging and open inspector. seeing if there are EISDIR errors.

[linear]

ENG-2007 Thrown error in expo-cli when remote debugging is enabled

Error: EISDIR: illegal operation on a directory, read
    at Object.readSync (node:fs:723:3)
    at tryReadSync (node:fs:433:20)
    at Object.readFileSync (node:fs:479:19)
    at UnableToResolveError.buildCodeFrameMessage (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:347:17)
    at new UnableToResolveError (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:333:35)
    at ModuleResolver.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:211:15)
    at DependencyGraph.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph.js:413:43)
    at /Users/wschurman/temp/qawat/node_modules/metro/src/lib/transformHelpers.js:317:42
    at /Users/wschurman/temp/qawat/node_modules/metro/src/Server.js:1471:14
    at Generator.next (<anonymous>)
Error: EISDIR: illegal operation on a directory, read
    at Object.readSync (node:fs:723:3)
    at tryReadSync (node:fs:433:20)
    at Object.readFileSync (node:fs:479:19)
    at UnableToResolveError.buildCodeFrameMessage (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:347:17)
    at new UnableToResolveError (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:333:35)
    at ModuleResolver.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:211:15)
    at DependencyGraph.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph.js:413:43)
    at /Users/wschurman/temp/qawat/node_modules/metro/src/lib/transformHelpers.js:317:42
    at /Users/wschurman/temp/qawat/node_modules/metro/src/Server.js:1471:14
    at Generator.next (<anonymous>)
Error: EISDIR: illegal operation on a directory, read
    at Object.readSync (node:fs:723:3)
    at tryReadSync (node:fs:433:20)
    at Object.readFileSync (node:fs:479:19)
    at UnableToResolveError.buildCodeFrameMessage (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:347:17)
    at new UnableToResolveError (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:333:35)
    at ModuleResolver.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph/ModuleResolution.js:211:15)
    at DependencyGraph.resolveDependency (/Users/wschurman/temp/qawat/node_modules/metro/src/node-haste/DependencyGraph.js:413:43)
    at /Users/wschurman/temp/qawat/node_modules/metro/src/lib/transformHelpers.js:317:42
    at /Users/wschurman/temp/qawat/node_modules/metro/src/Server.js:1471:14
    at Generator.next (<anonymous>)

Repro:

1. Init blank app
2. expo start
3. enable remote debugging
4. see error above in expo-cli

[EvanBacon]

LGTM