ProfileInfo APIs should not load layers when no projectDir is specified

[zFernand0]

We came across certain undesired behavior while investigating this issue (zowe/zowe-explorer-vscode#1802 (comment)).

When no projectDir is specified, the mProjectDir property defaults to / (C:\) and ProfileInfo attempts to load profiles in those directories.

         if (!teamCfgOpts.projectDir) {
            this.mLoadedConfig.mLayers[Layers.ProjectUser].exists = false;
            this.mLoadedConfig.mLayers[Layers.ProjectConfig].exists = false;
        }

This is not the same as disallowing the default look-up behavior. We still want to keep this behavior in the ProfileInfo APIs in order to keep ZE and CLI consistent. This snippet may illustrate what disabling all project config loading looks like when there is no VSCode workspace open

        if (teamCfgOpts.projectDir) {
            if (path.dirname(this.mLoadedConfig.mLayers[Layers.ProjectUser].path) !== teamCfgOpts.projectDir) 
                this.mLoadedConfig.mLayers[Layers.ProjectUser].exists = false;
            if (path.dirname(this.mLoadedConfig.mLayers[Layers.ProjectConfig].path) !== teamCfgOpts.projectDir) 
                this.mLoadedConfig.mLayers[Layers.ProjectConfig].exists = false;
        }