fix: handle alias file with no orgs prop

[cristiand391]

What does this PR do?

makes the alias accessor handle alias files that don't have the orgs property (we got 2 reports happening where they get a alias file with {}` as the content, should also fix users on the old key:value alias file format).

repro:

write {} to your alias file (~/.sfdx/alias.json)
run SF_ENV=development sf alias list, see error

then if you link this branch of core into plugin-settings, with the same alias file you shouldn't get the error.

expected

sfdx-core handles bad alias file, returns "no alias found"

actual result

*** Internal Diagnostic ***

TypeError: Cannot convert undefined or null to object
    at Function.entries (<anonymous>)
    at fileContentsRawToAliasStore (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/c
li/node_modules/@salesforce/core/lib/stateAggregator/accessors/aliasAccessor.js:245:27)
    at AliasAccessor.readFileToAliasStore (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@sales
force/cli/node_modules/@salesforce/core/lib/stateAggregator/accessors/aliasAccessor.js:187:31)
    at async AliasAccessor.init (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/cli/
node_modules/@salesforce/core/lib/stateAggregator/accessors/aliasAccessor.js:176:9)
    at async AliasAccessor.create (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/cl
i/node_modules/@salesforce/kit/lib/creatable.js:57:9)
    at async StateAggregator.init (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/cl
i/node_modules/@salesforce/core/lib/stateAggregator/stateAggregator.js:40:24)
    at async StateAggregator.create (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/
cli/node_modules/@salesforce/kit/lib/creatable.js:57:9)
    at async StateAggregator.getInstance (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesf
orce/cli/node_modules/@salesforce/core/lib/stateAggregator/stateAggregator.js:24:66)
    at async AliasList.run (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/cli/node_
modules/@salesforce/plugin-settings/lib/commands/alias/list.js:17:33)
    at async AliasList._run (/Users/cdominguez/.nvm/versions/node/v18.17.0/lib/node_modules/@salesforce/cli/node
_modules/@salesforce/plugin-settings/node_modules/@oclif/core/lib/command.js:117:22)
******

What issues does this PR fix or reference?

@W-14365013@