fix: add a better error message with invalid manifests

[shetzel]

What does this PR do?

throw an error during manifest parsing when a metadata type appears invalid, indicating a bad manifest file.

What issues does this PR fix or reference?

@W-11927256@

Functionality Before

"Cannot read property 'toLowerCase' of undefined"
forcedotcom/cli#1187

Functionality After

Invalid types definition in manifest file: package.xml
Found: ""

Testing:
Create a manifest file with an empty <types></types> definition inside and run sfdx force:source:retrieve -x package.xml

[mshanemc]

QA:

✅ got the error on both retrieve and deploy with a bad manifest

➜  qa-manifest-error ../../plugin-source/bin/dev force:source:retrieve -x mdapiOut/package.xml
ERROR running force:source:retrieve:  Invalid types definition in manifest file: mdapiOut/package.xml
Found: ""
Preparing retrieve request... done
➜  qa-manifest-error ../../plugin-source/bin/dev force:source:deploy -x mdapiOut/package.xml
ERROR running force:source:deploy:  Invalid types definition in manifest file: mdapiOut/package.xml
Found: ""

[gbutt-tr]

I believe this change may be causing an error to get thrown when an empty static resource folder is pushed. Should I create an issue for this, or is it expected behavior?

The only file i have in the reactBundle folder is an empty .git-keep file.

*** Pushing with SOAP API v54.0 ***
DEPLOY PROGRESS | ████████████████████████████████████████ | 3205/3205 Components
ERROR running force:source:push:  force-app/main/default/staticresources/reactBundle.resource-meta.xml: Expected source files for type 'StaticResource'
CLIError: timed out
    at Object.error (/opt/homebrew/Cellar/nvm/0.39.1_1/versions/node/v16.15.0/lib/node_modules/sfdx-cli/node_modules/@oclif/core/lib/errors/index.js:28:15)
    at /opt/homebrew/Cellar/nvm/0.39.1_1/versions/node/v16.15.0/lib/node_modules/sfdx-cli/node_modules/@oclif/core/lib/cli-ux/index.js:25:66
    at runNextTicks (node:internal/process/task_queues:61:5)
    at processTimers (node:internal/timers:499:9)
    at async flush (/opt/homebrew/Cellar/nvm/0.39.1_1/versions/node/v16.15.0/lib/node_modules/sfdx-cli/node_modules/@oclif/core/lib/cli-ux/index.js:124:9) {
  oclif: { exit: 2 },
  code: undefined
}
Updating source tracking... done